public TcpSink tcp() {
		if (tcpSink == null) {
			tcpSink = TcpSink.withDefaultPort();
		}
		return tcpSink;
	}
Construct a new TcpSink with the default target host taken from the environment and default port (1234)

@return an instance of TcpSink
spring-xd-integration-test/src/main/java/org/springframework/xd/integration/fixtures/Sinks.java