### Description
Adding an `onValidated` observer which will run every time a message is
received and validated. This comes from the necessity of precisely track
message deliveries and network activity.
`onRecv` observers run before any check is performed on the received
message, which means that it runs every time a duplicate or invalid
message arrives, which is inefficient and inaccurate for our purpose of
tracking only received, unique and valid messages. Therefore, adding
this extra option of running an observer for every message after all
validation checks pass.
* adding raises defect across the codebase
* use unittest2
* add windows deps caching
* update mingw link
* die on failed peerinfo initialization
* use result.expect instead of get
* use expect more consistently and rework inits
* use expect more consistently
* throw on missing public key
* remove unused closure annotation
* merge master
* gossipsub: unsubscribe fixes
* fix KeyError when updating metric of unsubscribed topic
* fix unsubscribe message not being sent to all peers causing them to
keep thinking we're still subscribed
* release memory earlier in a few places
* floodsub fix
In `async` functions, a closure environment is created for variables
that cross an await boundary - this closure environment is kept in
memory for the lifetime of the associated future - this means that
although _some_ variables are no longer used, they still take up memory
for a long time.
In Nimbus, message validation is processed in batches meaning the future
of an incoming gossip message stays around for quite a while - this
leads to memory consumption peaks of 100-200 mb when there are many
attestations in the pipeline.
To avoid excessive memory usage, it's generally better to move non-async
code into proc's such that the variables therein can be released earlier
- this includes the many hidden variables introduced by macro and
template expansion (ie chronicles that does expensive exception
handling)
* move seen table salt to floodsub, use there as well
* shorten seen table salt to size of hash
* avoid unnecessary memory allocations and copies in a few places
* factor out message scoring
* avoid reencoding outgoing message for every peer
* keep checking validators until reject (in case there's both reject and
ignore)
* `readOnce` avoids `readExactly` overhead for single-byte read
* genericAssign -> assign2
* properly propagate initiator information for gossipsub
* Fix pubsubpeer lifetime management
* restore old behavior
* tests fixing
* clamp backoff time value received
* fix member name collisions
* internal test fixes
* better names and explaining of the importance of transport direction
* fixes
* Refactor gossipsub into multiple modules
* splitup further gossipsub
* move more mesh related stuff to behavior
* fix internal tests
* fix PubSubPeer.outbound flag, make it more reliable
* use discard rather then _
* Remove unused connections in pubsubpeer, also removed wrong usages, add a disconnect bad peers parameter
* handle exceptions in disconnectPeer
* small fix
* use the proper disconnection procedure for gossip peers
* fixes, more metrics add test about disconnection
* hot fix possible null pointers in switch
* silly isnil sugar
* Fix and test gossip directPeer connections