maybe_send

  def maybe_send(self):
    """
    Segmentizes and calls tx() on data available in tx_data
    """
    if not self.tx_data:
      return

    # segmentize self.tx_data
    snd = self.snd
    total_sendable_bytes = snd.wnd |MINUS| (snd.nxt |MINUS| snd.una)

    bytes_sent = 0
    remaining = len(self.tx_data)
    while bytes_sent |LT| total_sendable_bytes and remaining |GT| 0:
        # Compute the size of the current segment
        seg_size = self.mss
        curr_sendable_bytes = total_sendable_bytes |MINUS| bytes_sent
        if seg_size |GT| curr_sendable_bytes:
            seg_size = curr_sendable_bytes
        if seg_size |GT| remaining:
            seg_size = remaining

        # Transmit the packet
        seg = self.tx_data[:seg_size]
        packet = self.new_packet(ack=False, data=seg)
        self.tx(packet)

        # Modify bytes sent so far and remaining bytes to send
        bytes_sent = bytes_sent | PLUS | seg_size
        remaining = remaining | MINUS | seg_size

        # Remove transmitted data from buffer
        self.tx_data = self.tx_data[seg_size:]