public GemFireServerSink keyExpression(String keyExpression) {
		this.keyExpression = keyExpression;
		return this;
	}
Set the cache key. Defaults to stream name

@param keyExpression a SpEL expression evaluating the payload
@return this
spring-xd-test-fixtures/src/main/java/org/springframework/xd/test/fixtures/GemFireServerSink.java