## Issue Addressed
#1056
## Proposed Changes
- Add a rate limiter to the RPC behaviour. This also means the rate limiting occurs just before the door to the application level, so the number of connections a peer opens does not affect this (this would happen in the future if put on the handler)
- The algorithm used is the leaky bucket as a meter / token bucket implemented the GCRA way
- Each protocol has its own limit. Due to the way the algorithm works, the "small" protocols have a hard limit, while bbrange and bbroot allow [burstiness](https://www.wikiwand.com/en/Burstiness). This is so that a peer can't request hundreds of individual requests expecting only one block in a short period of time, it also allows a peer to send two half size requests instead of one with max if they want to without getting limited, and.. it also allows a peer to request a batch of the maximum size and then send _appropriately spaced_ requests of really small sizes. From what I've seen in sync this is plausible when reaching the target slot.
## Additional Info
Needs to be heavily tested
## Issue Addressed
#1112
The logic is slightly different but still valid wrt to error handling.
- Inbound state is either Busy with a future that return the subtream (and info about the processing)
- The state machine works as follows:
- `Idle` with pending responses => `Busy`
- `Busy` => finished ? if so and there are new pending responses then `Busy`, if not then `Idle`
=> not finished remains `Busy`
- Add an `InboundInfo` for readability
- Other stuff:
- Close inbound substreams when all expected responses are sent
- Remove the error variants from `RPCCodedResponse` and use the codes instead
- Fix various spelling mistakes because I got sloppy last time
Sorry for the delay
Co-authored-by: Age Manning <Age@AgeManning.com>
