Remove `PendingSignRequests` queue from the sign module.
This closes#1027 by removing the pending sign requests queue dependency from the SendTransaction, SignMessage and Recover.
The main goal of this change is to remove async operations from node manager.
Additionally all of the signals from node manager are moved to status backend.
All of the async operation now will have the following behaviour:
- If node in the correct state exit immediatly without error
- If node not in the correct state exit immediatly with error
- In all other cases spawn a goroutine with wanted operation
- All the progress regarding that operation will be reported
by using signals
- Signals should be handled in once place, which is StatusBackend
There are 2 potentially breaking changes:
- Empty event field will be ommited when Envelope is sent to a client
- All errors will be delivered to a client as an Envelope, previously
some errors (NodeExists, NoRunningNode) were delivered synchronously
Signed-off-by: Dmitry Shulyak <yashulyak@gmail.com>