This TCP flag instructs the sending system to transmit all buffered data immediately.

SYN (Synchronize) is a TCP flag used to initiate a connection between two hosts.

RST (Reset) is a TCP flag used to abruptly terminate a connection or refuse a connection attempt.

The PSH (Push) flag in a TCP segment signals to the receiving application to immediately process and deliver all data currently in the TCP receive buffer, rather than waiting for the buffer to fill or for an application-specific read operation. This ensures that data is sent and processed promptly.

URG (Urgent) indicates that a segment contains urgent data and that the urgent pointer field in the TCP header is significant, allowing out-of-band processing, but it doesn't primarily deal with immediate transmission of all buffered data.

FIN (Finish) is a TCP flag used to gracefully terminate a connection.