docs: def read_tcp_size(conn, size):
    """Read `size` number of bytes from `conn`, retrying as needed."""
    chunks = []
    bytes_read = 0
    while bytes_read < size:
      chunk = conn.recv(size - bytes_read)
      if not chunk:
        if bytes_read > 0:
          logging.warning("Incomplete read: %s of %s.", bytes_read, size)
        return
      chunks.append(chunk)
      bytes_read += len(chunk)
    return b"".join(chunks)