Improve P2PStream buffering

[mattsse]

Describe the feature

we currently have a buffer:

https://github.com/paradigmxyz/reth/blob/ff9a42ae8fbf441f4fb9ca8dcea84c765b284721/crates/net/eth-wire/src/p2pstream.rs#L244-L245

TODO

• remove buffer
• update how pings are processed, because if we now go through the Sink API, then this must be stored as options that we optionally need to keep around
• if we modify the poll logic in p2pstream then we also need to manually add a flush call at the callsite https://github.com/paradigmxyz/reth/blob/ff9a42ae8fbf441f4fb9ca8dcea84c765b284721/crates/net/network/src/session/active.rs#L569-L569

also ptal at the Sink docs if unfamiliar with the Sink API

Additional context

No response

[MatteoMer]

hey! Would love to work on this 🫡

[jenpaff]

hey! Would love to work on this 🫡

assigned !