message: Fix off-by-one error preventing empty messages with headers from being parsed properly
diff: @@ -241,7 +241,7 @@ pub(crate) fn decode(mut stream: impl BufRead) -> io::Result<Option<ServerOp>> {
  )
  })?;
  - if num_bytes <= num_header_bytes {
  + if num_bytes < num_header_bytes {
  return Err(Error::new(
  ErrorKind::InvalidInput,
  "number of header bytes was greater than or equal to the \
  