While working on a DTLS implementation, and looking at a few depending/related projects, i discovered that there's a real absence of a "Framed Reader/Writer", the current
Write trait assumes a stream of data, and models reading/writing partial chunks entirely off of that.
UdpSocket does not implement Write + Read (for good reason), yet i still would like it to be somewhat generic to address through a trait bound, but that's where i discovered there is no trait bound of this type.
What i'm looking for is something along the lines of "Write/Read either an entire frame/chunk of bytes, or nothing at all", an ethernet/UDP frame, a websocket frame, or another "frame" of data.
In the case of UDP, these frames may be unordered/unreliable, but they would be framed. In the case of WebSockets, they'd be ordered and reliable.
Thus, the only functionality that this trait would give is "I will read/write either one frame of data as I see it.", which is a lot weaker than
Write, but could still be helpful, as it guarantees a bound of ordered bytes, outside of which these bounds can arrive in any order. This could make protocols with in-band sequencing (aforementioned DTLS, CoAP, or even TCP/IP on top of Ethernet framing) able to generically use this API.
Has such an API ever been considered? If not, would there be interest in such a thing?