The previous implementation of the *test* was flaky, and this irons
out some of those problems. The primary assertion that was failing
(less than 1% of the time) was an error on close that I think we
shouldn't care about.
The main (and minor) win of this PR is that the transport is fully the
responsibility of the router and the node doesn't need to be responsible for its lifecylce.
## Description
Internalize some libs. This reduces the amount ot public API tendermint is supporting. The moved libraries are mainly ones that are used within Tendermint-core.
This revises the new P2P `Transport` interface and does some preliminary code cleanups and simplifications.
The major change here is to add `Connection.Handshake()` for performing node handshakes (once the stream transport API is implemented, this can be done entirely independent of the transport). This moves most of the handshaking logic into the `Router`, such as prevention of head-of-line blocking, validation of peer's `NodeInfo`, controlling timeouts, and so on. This significantly simplifies transports, completely removes the need for internal goroutines, and shares common logic across all transports. This also allows varying the handshake `NodeInfo` across peers, e.g. to vary `ListenAddr`. Similarly, connection filtering is also moved into the switch/router so that it can be shared between transports.
This patches over a test data race where the logger would try to read struct internals via `reflect` while these were concurrently modified (specifically `MemoryTransport.closeOnce`).
This improves the `peerStore` prototype by e.g.:
* Using a database with Protobuf for persistence, but also keeping full peer set in memory for performance.
* Simplifying the API, by taking/returning struct copies for safety, and removing errors for in-memory operations.
* Caching the ranked peer set, as a temporary solution until a better data structure is implemented.
* Adding `PeerManagerOptions.MaxPeers` and pruning the peer store (based on rank) when it's full.
* Rewriting `PeerAddress` to be independent of `url.URL`, normalizing it and tightening semantics.
Sam Kleinman
Callum Waters
Marko
Erik Grinaker