public static <M> MessageStreamAssert<M> that(String id, MessageStream<M> messageStream, Serde<M> serde) {
    return new MessageStreamAssert<>(id, messageStream, serde);
  }
Constructors a MessageStreamAssert with an id and serde
@param id unique id
@param messageStream represents messageStream that you want to assert on
@param serde serde used to desialize messageStream
@param <M> represents type of Message
@return MessageStreamAssert that returns the the messages in the stream
samza-test/src/main/java/org/apache/samza/test/framework/MessageStreamAssert.java