The SendTimeout property determines the amount of time that the Send method will block until it is able to return successfully. This time is measured in milliseconds.
After you call the Write method, the underlying Socket returns the number of bytes actually sent to the host. The SendTimeout property determines the amount of time a TcpClient will wait before receiving the number of bytes returned. If the time-out expires before the Send method successfully completes, TcpClient will throw a SocketException. There is no time-out by default.
Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows CE Platform Note:
In .NET Compact Framework applications, the SendTimeout enumeration value is supported but reserved for future use. Because the SendTimeout property uses this enumeration value, it will raise SocketException until the enumeration value is available in a future release of the .NET Compact Framework.