pub fn read_payload<R: BufRead>(
reader: &mut R,
) -> Result<Option<String>, String>Expand description
Read a JSON-RPC payload from a buffered reader.
Reads headers until it finds Content-Length: N, then reads exactly N
bytes of body. Returns None on EOF and Err on malformed input.
Behavioral contract (must be preserved by any caller relying on it):
the Content-Length header match is case-insensitive, the body is read
with read_exact for exactly N bytes, and a single optional trailing
\r\n (or bare \n) between messages is consumed.