## Issue Addressed
N/A
## Proposed Changes
This PR limits the length of the stream received by the snappy decoder to be the maximum allowed size for the received rpc message type. Also adds further checks to ensure that the length specified in the rpc [encoding-dependent header](https://github.com/ethereum/eth2.0-specs/blob/dev/specs/phase0/p2p-interface.md#encoding-strategies) is within the bounds for the rpc message type being decoded.
## Issue Addressed
N/A
## Proposed Changes
Adds the following check from the spec
> A reader SHOULD NOT read more than max_encoded_len(n) bytes after reading the SSZ length-prefix n from the header.
## Issue Addressed
#1421
## Proposed Changes
Bounding the error_message that can be returned for RPC domain errors
Co-authored-by: Age Manning <Age@AgeManning.com>
## 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>
