code: def read_until(stream, delimiter, max_bytes=16):
      
  
      buf = bytearray()
      delim_len = len(delimiter)
  
      while len(buf) < max_bytes:
          c = stream.read(1)
  
          if not c:
              break
  
          buf += c
          if buf[-delim_len:] == delimiter:
              return bytes(buf[:-delim_len])
docs: Read until we have found the given delimiter.
  
      :param file stream: readable file-like object.
      :param bytes delimiter: delimiter string.
      :param int max_bytes: maximum bytes to read.
  
      :rtype: bytes|None