Make `stream timeout` and `maximum concurrent streams` per connection configurable in the identify protocol.

Description

I would like to propose the following two constants, namely :-

1. stream_timeout
2. max_concurrent_streams_per_connection

defined here be made configurable via Identify Behaviour config defined here.

Motivation

In a large peer-to-peer (p2p) network with a lot of peers attempting to a dial a peer via swarm, some subsequent IdentifyReceived events are never triggered due to the active streams timing out or not having enough concurrent streams configured per connection.

Currently there is no way to increase this timeout or allow more concurrent streams as they are hardcoded to 60s and 10 respectively on identify handlers.

I would love to have these two attributes be made configurable such that the user inheriting the library can choose to set a value from config and the default be set to the original 60s and 10 respectively.

Current Implementation

Current implementation:

/protocol/identify/src/handler.rs

const STREAM_TIMEOUT: Duration = Duration::from_secs(60);
const MAX_CONCURRENT_STREAMS_PER_CONNECTION: usize = 10;

/protocol/identify/src/handler.rs

impl Handler {
    /// Creates a new `Handler`.
    pub fn new(
        interval: Duration,
        remote_peer_id: PeerId,
        public_key: PublicKey,
        protocol_version: String,
        agent_version: String,
        observed_addr: Multiaddr,
        external_addresses: HashSet<Multiaddr>,
    ) -> Self {
        Self {
            remote_peer_id,
            events: SmallVec::new(),
            active_streams: futures_bounded::FuturesSet::new(
                STREAM_TIMEOUT,
                MAX_CONCURRENT_STREAMS_PER_CONNECTION,
            ),
            ...

Are you planning to do it yourself in a pull request ?

Yes

Start with protocols/identify/src/handler.rs, where the stream timeout and per-connection concurrency constants are used in Handler::new. Then inspect the Identify Behaviour config in protocols/identify/src/behaviour.rs and trace how configuration reaches the handler. Done means both values are configurable through that config while retaining defaults of 60 seconds and 10 streams.