@Override
		public void describeTo(Description description) {
			description.appendDescriptionOf(matcher);
		}
A matcher on the String contents of the sink, that delegates to another (String) matcher.

<p>
Instances are to be constructed using
{@code org.springframework.xd.shell.command.fixtures.XDMatchers#hasContentsThat}.

@author Eric Bottard
spring-xd-test-fixtures/src/main/java/org/springframework/xd/test/fixtures/FileSink.java