# beacon_chain # Copyright (c) 2018-2023 Status Research & Development GmbH # Licensed and distributed under either of # * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT). # * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0). # at your option. This file may not be copied, modified, or distributed except according to those terms. when (NimMajor, NimMinor) < (1, 4): {.push raises: [Defect].} else: {.push raises: [].} import stew/results, chronicles, chronos, metrics, ../spec/signatures_batch, ../sszdump from ../consensus_object_pools/consensus_manager import ConsensusManager, checkNextProposer, optimisticExecutionPayloadHash, runForkchoiceUpdated, runForkchoiceUpdatedDiscardResult, runProposalForkchoiceUpdated, shouldSyncOptimistically, updateHead, updateHeadWithExecution from ../beacon_clock import GetBeaconTimeFn, toFloatSeconds from ../consensus_object_pools/block_dag import BlockRef, root, slot from ../consensus_object_pools/block_pools_types import EpochRef, VerifierError from ../consensus_object_pools/block_quarantine import addOrphan, addUnviable, pop, removeOrphan from ../validators/validator_monitor import MsgSource, ValidatorMonitor, registerAttestationInBlock, registerBeaconBlock, registerSyncAggregateInBlock from ../spec/datatypes/eip4844 import BlobsSidecar from ../spec/state_transition_block import validate_blobs_sidecar export sszdump, signatures_batch # Block Processor # ------------------------------------------------------------------------------ # The block processor moves blocks from "Incoming" to "Consensus verified" declareHistogram beacon_store_block_duration_seconds, "storeBlock() duration", buckets = [0.25, 0.5, 1, 2, 4, 8, Inf] type BlockEntry* = object blck*: ForkedSignedBeaconBlock blobs*: Opt[eip4844.BlobsSidecar] resfut*: Future[Result[void, VerifierError]] queueTick*: Moment # Moment when block was enqueued validationDur*: Duration # Time it took to perform gossip validation src*: MsgSource BlockProcessor* = object ## This manages the processing of blocks from different sources ## Blocks and attestations are enqueued in a gossip-validated state ## ## from: ## - Gossip (when synced) ## - SyncManager (during sync) ## - RequestManager (missing ancestor blocks) ## ## are then consensus-verified and added to: ## - the blockchain DAG ## - database ## - attestation pool ## - fork choice ## ## The processor will also reinsert blocks from the quarantine, should a ## parent be found. # Config # ---------------------------------------------------------------- dumpEnabled: bool dumpDirInvalid: string dumpDirIncoming: string # Producers # ---------------------------------------------------------------- blockQueue: AsyncQueue[BlockEntry] # Consumer # ---------------------------------------------------------------- consensusManager: ref ConsensusManager ## Blockchain DAG, AttestationPool and Quarantine ## Blockchain DAG, AttestationPool, Quarantine, and Eth1Manager validatorMonitor: ref ValidatorMonitor getBeaconTime: GetBeaconTimeFn verifier: BatchVerifier NewPayloadStatus {.pure.} = enum valid notValid invalid noResponse ProcessingStatus {.pure.} = enum completed notCompleted proc addBlock*( self: var BlockProcessor, src: MsgSource, blck: ForkedSignedBeaconBlock, blobs: Opt[eip4844.BlobsSidecar], resfut: Future[Result[void, VerifierError]] = nil, validationDur = Duration()) # Initialization # ------------------------------------------------------------------------------ proc new*(T: type BlockProcessor, dumpEnabled: bool, dumpDirInvalid, dumpDirIncoming: string, rng: ref HmacDrbgContext, taskpool: TaskPoolPtr, consensusManager: ref ConsensusManager, validatorMonitor: ref ValidatorMonitor, getBeaconTime: GetBeaconTimeFn): ref BlockProcessor = (ref BlockProcessor)( dumpEnabled: dumpEnabled, dumpDirInvalid: dumpDirInvalid, dumpDirIncoming: dumpDirIncoming, blockQueue: newAsyncQueue[BlockEntry](), consensusManager: consensusManager, validatorMonitor: validatorMonitor, getBeaconTime: getBeaconTime, verifier: BatchVerifier(rng: rng, taskpool: taskpool) ) # Sync callbacks # ------------------------------------------------------------------------------ func hasBlocks*(self: BlockProcessor): bool = self.blockQueue.len() > 0 # Storage # ------------------------------------------------------------------------------ proc dumpInvalidBlock*( self: BlockProcessor, signedBlock: ForkySignedBeaconBlock) = if self.dumpEnabled: dump(self.dumpDirInvalid, signedBlock) proc dumpBlock[T]( self: BlockProcessor, signedBlock: ForkySignedBeaconBlock, res: Result[T, VerifierError]) = if self.dumpEnabled and res.isErr: case res.error of VerifierError.Invalid: self.dumpInvalidBlock(signedBlock) of VerifierError.MissingParent: dump(self.dumpDirIncoming, signedBlock) else: discard from ../consensus_object_pools/block_clearance import addBackfillBlock, addHeadBlock from ../beacon_chain_db import putBlobsSidecar proc storeBackfillBlock( self: var BlockProcessor, signedBlock: ForkySignedBeaconBlock, blobs: Opt[eip4844.BlobsSidecar]): Result[void, VerifierError] = # The block is certainly not missing any more self.consensusManager.quarantine[].missing.del(signedBlock.root) # Establish blob viability before calling addbackfillBlock to avoid # writing the block in case of blob error. let blobsOk = when typeof(signedBlock).toFork() >= BeaconBlockFork.EIP4844: blobs.isSome() and not validate_blobs_sidecar(signedBlock.message.slot, hash_tree_root(signedBlock.message), signedBlock.message .body.blob_kzg_commitments.asSeq, blobs.get()).isOk() else: true if not blobsOk: return err(VerifierError.Invalid) let res = self.consensusManager.dag.addBackfillBlock(signedBlock) if res.isErr(): case res.error of VerifierError.MissingParent: if signedBlock.message.parent_root in self.consensusManager.quarantine[].unviable: # DAG doesn't know about unviable ancestor blocks - we do! Translate # this to the appropriate error so that sync etc doesn't retry the block self.consensusManager.quarantine[].addUnviable(signedBlock.root) return err(VerifierError.UnviableFork) of VerifierError.UnviableFork: # Track unviables so that descendants can be discarded properly self.consensusManager.quarantine[].addUnviable(signedBlock.root) else: discard return res if blobs.isSome(): # Only store blobs after successfully establishing block viability. self.consensusManager.dag.db.putBlobsSidecar(blobs.get()) res from web3/engine_api_types import PayloadExecutionStatus, PayloadStatusV1 from ../eth1/eth1_monitor import Eth1Monitor, asEngineExecutionPayload, ensureDataProvider, newPayload proc expectValidForkchoiceUpdated( eth1Monitor: Eth1Monitor, headBlockHash, safeBlockHash, finalizedBlockHash: Eth2Digest, receivedBlock: ForkySignedBeaconBlock): Future[void] {.async.} = let (payloadExecutionStatus, _) = await eth1Monitor.runForkchoiceUpdated( headBlockHash, safeBlockHash, finalizedBlockHash) receivedExecutionBlockHash = when typeof(receivedBlock).toFork >= BeaconBlockFork.Bellatrix: receivedBlock.message.body.execution_payload.block_hash else: # https://github.com/nim-lang/Nim/issues/19802 (static(default(Eth2Digest))) # Only called when expecting this to be valid because `newPayload` or some # previous `forkchoiceUpdated` had already marked it as valid. However, if # it's not the block that was received, don't info/warn either way given a # relative lack of immediate evidence. if receivedExecutionBlockHash != headBlockHash: return case payloadExecutionStatus of PayloadExecutionStatus.valid: # situation nominal discard of PayloadExecutionStatus.accepted, PayloadExecutionStatus.syncing: info "execution payload forkChoiceUpdated status ACCEPTED/SYNCING, but was previously VALID", payloadExecutionStatus = $payloadExecutionStatus, headBlockHash, safeBlockHash, finalizedBlockHash, receivedBlock = shortLog(receivedBlock) of PayloadExecutionStatus.invalid, PayloadExecutionStatus.invalid_block_hash: warn "execution payload forkChoiceUpdated status INVALID, but was previously VALID", payloadExecutionStatus = $payloadExecutionStatus, headBlockHash, safeBlockHash, finalizedBlockHash, receivedBlock = shortLog(receivedBlock) from ../consensus_object_pools/attestation_pool import addForkChoice, selectOptimisticHead, BeaconHead from ../consensus_object_pools/blockchain_dag import is_optimistic, loadExecutionBlockRoot, markBlockVerified from ../consensus_object_pools/block_dag import shortLog from ../consensus_object_pools/spec_cache import get_attesting_indices from ../spec/datatypes/phase0 import TrustedSignedBeaconBlock from ../spec/datatypes/altair import SignedBeaconBlock from ../spec/datatypes/bellatrix import SignedBeaconBlock from eth/async_utils import awaitWithTimeout from ../spec/datatypes/bellatrix import ExecutionPayload, SignedBeaconBlock from ../spec/datatypes/capella import ExecutionPayload, SignedBeaconBlock, asTrusted, shortLog proc newExecutionPayload*( eth1Monitor: Eth1Monitor, executionPayload: bellatrix.ExecutionPayload | capella.ExecutionPayload | eip4844.ExecutionPayload): Future[Opt[PayloadExecutionStatus]] {.async.} = if eth1Monitor.isNil: return Opt.none PayloadExecutionStatus debug "newPayload: inserting block into execution engine", parentHash = executionPayload.parent_hash, blockHash = executionPayload.block_hash, stateRoot = shortLog(executionPayload.state_root), receiptsRoot = shortLog(executionPayload.receipts_root), prevRandao = shortLog(executionPayload.prev_randao), blockNumber = executionPayload.block_number, gasLimit = executionPayload.gas_limit, gasUsed = executionPayload.gas_used, timestamp = executionPayload.timestamp, extraDataLen = executionPayload.extra_data.len, baseFeePerGas = $executionPayload.base_fee_per_gas, numTransactions = executionPayload.transactions.len # https://github.com/ethereum/execution-apis/blob/v1.0.0-beta.1/src/engine/specification.md#request const NEWPAYLOAD_TIMEOUT = 8.seconds try: let payloadResponse = awaitWithTimeout( eth1Monitor.newPayload( executionPayload.asEngineExecutionPayload), NEWPAYLOAD_TIMEOUT): info "newPayload: newPayload timed out" return Opt.none PayloadExecutionStatus # Placeholder for type system PayloadStatusV1(status: PayloadExecutionStatus.syncing) payloadStatus = payloadResponse.status debug "newPayload: succeeded", parentHash = executionPayload.parent_hash, blockHash = executionPayload.block_hash, blockNumber = executionPayload.block_number, payloadStatus = $payloadStatus return Opt.some payloadStatus except CatchableError as err: warn "newPayload failed - check execution client", msg = err.msg, parentHash = shortLog(executionPayload.parent_hash), blockHash = shortLog(executionPayload.block_hash), blockNumber = executionPayload.block_number return Opt.none PayloadExecutionStatus # TODO investigate why this seems to allow compilation even though it doesn't # directly address eip4844.ExecutionPayload when complaint was that it didn't # know about "eip4844" from ../spec/datatypes/eip4844 import SignedBeaconBlock, asTrusted, shortLog proc getExecutionValidity( eth1Monitor: Eth1Monitor, blck: bellatrix.SignedBeaconBlock | capella.SignedBeaconBlock | eip4844.SignedBeaconBlock): Future[NewPayloadStatus] {.async.} = # Eth1 syncing is asynchronous from this # TODO self.consensusManager.eth1Monitor.ttdReached # should gate this when it works more reliably # TODO detect have-TTD-but-not-is_execution_block case, and where # execution payload was non-zero when TTD detection more reliable if not blck.message.is_execution_block: return NewPayloadStatus.valid # vacuously if eth1Monitor.isNil: return NewPayloadStatus.noResponse try: # Minimize window for Eth1 monitor to shut down connection await eth1Monitor.ensureDataProvider() let executionPayloadStatus = await newExecutionPayload( eth1Monitor, blck.message.body.execution_payload) if executionPayloadStatus.isNone: return NewPayloadStatus.noResponse case executionPayloadStatus.get of PayloadExecutionStatus.invalid, PayloadExecutionStatus.invalid_block_hash: debug "getExecutionValidity: execution payload invalid", executionPayloadStatus = $executionPayloadStatus.get, blck = shortLog(blck) return NewPayloadStatus.invalid of PayloadExecutionStatus.syncing, PayloadExecutionStatus.accepted: return NewPayloadStatus.notValid of PayloadExecutionStatus.valid: return NewPayloadStatus.valid except CatchableError as err: error "getExecutionValidity: newPayload failed", err = err.msg return NewPayloadStatus.noResponse proc storeBlock*( self: ref BlockProcessor, src: MsgSource, wallTime: BeaconTime, signedBlock: ForkySignedBeaconBlock, blobs: Opt[eip4844.BlobsSidecar], queueTick: Moment = Moment.now(), validationDur = Duration()): Future[Result[BlockRef, (VerifierError, ProcessingStatus)]] {.async.} = ## storeBlock is the main entry point for unvalidated blocks - all untrusted ## blocks, regardless of origin, pass through here. When storing a block, ## we will add it to the dag and pass it to all block consumers that need ## to know about it, such as the fork choice and the monitoring let attestationPool = self.consensusManager.attestationPool startTick = Moment.now() vm = self.validatorMonitor dag = self.consensusManager.dag payloadStatus = when typeof(signedBlock).toFork() >= BeaconBlockFork.Bellatrix: await self.consensusManager.eth1Monitor.getExecutionValidity(signedBlock) else: NewPayloadStatus.valid # vacuously payloadValid = payloadStatus == NewPayloadStatus.valid # The block is certainly not missing any more self.consensusManager.quarantine[].missing.del(signedBlock.root) if NewPayloadStatus.invalid == payloadStatus: self.consensusManager.quarantine[].addUnviable(signedBlock.root) return err((VerifierError.UnviableFork, ProcessingStatus.completed)) if NewPayloadStatus.noResponse == payloadStatus: # When the execution layer is not available to verify the payload, we do the # required check on the CL side instead and proceed as if the EL was syncing # Client software MUST validate blockHash value as being equivalent to # Keccak256(RLP(ExecutionBlockHeader)) # https://github.com/ethereum/execution-apis/blob/v1.0.0-beta.1/src/engine/specification.md#specification when typeof(signedBlock).toFork() >= BeaconBlockFork.Bellatrix: template payload(): auto = signedBlock.message.body.execution_payload if payload.block_hash != payload.compute_execution_block_hash(): debug "Execution block hash validation failed", execution_payload = payload doAssert strictVerification notin dag.updateFlags self.consensusManager.quarantine[].addUnviable(signedBlock.root) return err((VerifierError.Invalid, ProcessingStatus.completed)) else: discard # We'll also remove the block as an orphan: it's unlikely the parent is # missing if we get this far - should that be the case, the block will # be re-added later self.consensusManager.quarantine[].removeOrphan(signedBlock) # Establish blob viability before calling addHeadBlock to avoid # writing the block in case of blob error. when typeof(signedBlock).toFork() >= BeaconBlockFork.EIP4844: if blobs.isSome() and not validate_blobs_sidecar(signedBlock.message.slot, hash_tree_root(signedBlock.message), signedBlock.message .body.blob_kzg_commitments.asSeq, blobs.get()).isOk(): return err((VerifierError.Invalid, ProcessingStatus.completed)) type Trusted = typeof signedBlock.asTrusted() let blck = dag.addHeadBlock(self.verifier, signedBlock, payloadValid) do ( blckRef: BlockRef, trustedBlock: Trusted, epochRef: EpochRef, unrealized: FinalityCheckpoints): # Callback add to fork choice if valid attestationPool[].addForkChoice( epochRef, blckRef, unrealized, trustedBlock.message, wallTime) vm[].registerBeaconBlock( src, wallTime, trustedBlock.message) for attestation in trustedBlock.message.body.attestations: for validator_index in dag.get_attesting_indices(attestation): vm[].registerAttestationInBlock(attestation.data, validator_index, trustedBlock.message.slot) withState(dag[].clearanceState): when stateFork >= BeaconStateFork.Altair and Trusted isnot phase0.TrustedSignedBeaconBlock: # altair+ for i in trustedBlock.message.body.sync_aggregate.sync_committee_bits.oneIndices(): vm[].registerSyncAggregateInBlock( trustedBlock.message.slot, trustedBlock.root, forkyState.data.current_sync_committee.pubkeys.data[i]) self[].dumpBlock(signedBlock, blck) # There can be a scenario where we receive a block we already received. # However this block was before the last finalized epoch and so its parent # was pruned from the ForkChoice. if blck.isErr(): case blck.error() of VerifierError.MissingParent: if signedBlock.message.parent_root in self.consensusManager.quarantine[].unviable: # DAG doesn't know about unviable ancestor blocks - we do! Translate # this to the appropriate error so that sync etc doesn't retry the block self.consensusManager.quarantine[].addUnviable(signedBlock.root) return err((VerifierError.UnviableFork, ProcessingStatus.completed)) if not self.consensusManager.quarantine[].addOrphan( dag.finalizedHead.slot, ForkedSignedBeaconBlock.init(signedBlock), blobs): debug "Block quarantine full", blockRoot = shortLog(signedBlock.root), blck = shortLog(signedBlock.message), signature = shortLog(signedBlock.signature) of VerifierError.UnviableFork: # Track unviables so that descendants can be discarded properly self.consensusManager.quarantine[].addUnviable(signedBlock.root) else: discard return err((blck.error, ProcessingStatus.completed)) # write blobs now that block has been written. if blobs.isSome(): self.consensusManager.dag.db.putBlobsSidecar(blobs.get()) let storeBlockTick = Moment.now() # Eagerly update head: the incoming block "should" get selected. # # storeBlock gets called from validator_duties, which depends on its not # blocking progress any longer than necessary, and processBlock here, in # which case it's fine to await for a while on engine API results. # # Three general scenarios: (1) pre-merge; (2) merge, already `VALID` by way # of `newPayload`; (3) optimistically imported, need to call fcU before DAG # updateHead. Handle each with as little async latency as feasible. if payloadValid: self.consensusManager.dag.markBlockVerified( self.consensusManager.quarantine[], signedBlock.root) # Grab the new head according to our latest attestation data; determines how # async this needs to be. let wallSlot = wallTime.slotOrZero newHead = attestationPool[].selectOptimisticHead( wallSlot.start_beacon_time) if newHead.isOk: template eth1Monitor(): auto = self.consensusManager.eth1Monitor if self.consensusManager[].shouldSyncOptimistically(wallSlot): # Optimistic head is far in the future; report it as head block to EL. # Note that the specification allows an EL client to skip fcU processing # if an update to an ancestor is requested. # > Client software MAY skip an update of the forkchoice state and MUST # NOT begin a payload build process if `forkchoiceState.headBlockHash` # references an ancestor of the head of canonical chain. # https://github.com/ethereum/execution-apis/blob/v1.0.0-beta.1/src/engine/specification.md#engine_forkchoiceupdatedv1 # # However, in practice, an EL client may not have completed importing all # block headers, so may be unaware of a block's ancestor status. # Therefore, hopping back and forth between the optimistic head and the # chain DAG head does not work well in practice, e.g., Geth: # - "Beacon chain gapped" from DAG head to optimistic head, # - followed by "Beacon chain reorged" from optimistic head back to DAG. self.consensusManager[].updateHead(newHead.get.blck) asyncSpawn eth1Monitor.runForkchoiceUpdatedDiscardResult( headBlockHash = self.consensusManager[].optimisticExecutionPayloadHash, safeBlockHash = newHead.get.safeExecutionPayloadHash, finalizedBlockHash = newHead.get.finalizedExecutionPayloadHash) else: let headExecutionPayloadHash = self.consensusManager.dag.loadExecutionBlockRoot(newHead.get.blck) wallSlot = self.getBeaconTime().slotOrZero if headExecutionPayloadHash.isZero: # Blocks without execution payloads can't be optimistic. self.consensusManager[].updateHead(newHead.get.blck) elif not self.consensusManager.dag.is_optimistic newHead.get.blck.root: # Not `NOT_VALID`; either `VALID` or `INVALIDATED`, but latter wouldn't # be selected as head, so `VALID`. `forkchoiceUpdated` necessary for EL # client only. self.consensusManager[].updateHead(newHead.get.blck) if self.consensusManager.checkNextProposer(wallSlot).isNone: # No attached validator is next proposer, so use non-proposal fcU asyncSpawn eth1Monitor.expectValidForkchoiceUpdated( headBlockHash = headExecutionPayloadHash, safeBlockHash = newHead.get.safeExecutionPayloadHash, finalizedBlockHash = newHead.get.finalizedExecutionPayloadHash, receivedBlock = signedBlock) else: # Some attached validator is next proposer, so prepare payload. As # updateHead() updated the DAG head, runProposalForkchoiceUpdated, # which needs the state corresponding to that head block, can run. asyncSpawn self.consensusManager.runProposalForkchoiceUpdated( wallSlot) else: asyncSpawn self.consensusManager.updateHeadWithExecution( newHead.get, self.getBeaconTime) else: warn "Head selection failed, using previous head", head = shortLog(self.consensusManager.dag.head), wallSlot let updateHeadTick = Moment.now() queueDur = startTick - queueTick storeBlockDur = storeBlockTick - startTick updateHeadDur = updateHeadTick - storeBlockTick beacon_store_block_duration_seconds.observe(storeBlockDur.toFloatSeconds()) debug "Block processed", localHeadSlot = self.consensusManager.dag.head.slot, blockSlot = blck.get().slot, validationDur, queueDur, storeBlockDur, updateHeadDur for quarantined in self.consensusManager.quarantine[].pop(blck.get().root): # Process the blocks that had the newly accepted block as parent self[].addBlock(MsgSource.gossip, quarantined[0], quarantined[1]) return Result[BlockRef, (VerifierError, ProcessingStatus)].ok blck.get # Enqueue # ------------------------------------------------------------------------------ proc addBlock*( self: var BlockProcessor, src: MsgSource, blck: ForkedSignedBeaconBlock, blobs: Opt[eip4844.BlobsSidecar], resfut: Future[Result[void, VerifierError]] = nil, validationDur = Duration()) = ## Enqueue a Gossip-validated block for consensus verification # Backpressure: # There is no backpressure here - producers must wait for `resfut` to # constrain their own processing # Producers: # - Gossip (when synced) # - SyncManager (during sync) # - RequestManager (missing ancestor blocks) withBlck(blck): if blck.message.slot <= self.consensusManager.dag.finalizedHead.slot: # let backfill blocks skip the queue - these are always "fast" to process # because there are no state rewinds to deal with let res = self.storeBackfillBlock(blck, blobs) if resfut != nil: resfut.complete(res) return try: self.blockQueue.addLastNoWait(BlockEntry( blck: blck, blobs: blobs, resfut: resfut, queueTick: Moment.now(), validationDur: validationDur, src: src)) except AsyncQueueFullError: raiseAssert "unbounded queue" # Event Loop # ------------------------------------------------------------------------------ proc processBlock( self: ref BlockProcessor, entry: BlockEntry) {.async.} = logScope: blockRoot = shortLog(entry.blck.root) let wallTime = self.getBeaconTime() (afterGenesis, wallSlot) = wallTime.toSlot() if not afterGenesis: error "Processing block before genesis, clock turned back?" quit 1 let res = withBlck(entry.blck): await self.storeBlock( entry.src, wallTime, blck, entry.blobs, entry.queueTick, entry.validationDur) if res.isErr and res.error[1] == ProcessingStatus.notCompleted: # When an execution engine returns an error or fails to respond to a # payload validity request for some block, a consensus engine: # - MUST NOT optimistically import the block. # - MUST NOT apply the block to the fork choice store. # - MAY queue the block for later processing. # https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.0/sync/optimistic.md#execution-engine-errors await sleepAsync(chronos.seconds(1)) self[].addBlock( entry.src, entry.blck, entry.blobs, entry.resfut, entry.validationDur) # To ensure backpressure on the sync manager, do not complete these futures. return if entry.resfut != nil: entry.resfut.complete( if res.isOk(): Result[void, VerifierError].ok() else: Result[void, VerifierError].err(res.error()[0])) proc runQueueProcessingLoop*(self: ref BlockProcessor) {.async.} = while true: # Cooperative concurrency: one block per loop iteration - because # we run both networking and CPU-heavy things like block processing # on the same thread, we need to make sure that there is steady progress # on the networking side or we get long lockups that lead to timeouts. const # We cap waiting for an idle slot in case there's a lot of network traffic # taking up all CPU - we don't want to _completely_ stop processing blocks # in this case - doing so also allows us to benefit from more batching / # larger network reads when under load. idleTimeout = 10.milliseconds discard await idleAsync().withTimeout(idleTimeout) await self.processBlock(await self[].blockQueue.popFirst())