public SendUsersMessageResponse withRequestId(String requestId) {
        setRequestId(requestId);
        return this;
    }
<p>
The unique identifier that was assigned to the message request.
</p>

@param requestId
       The unique identifier that was assigned to the message request.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-pinpoint/src/main/java/com/amazonaws/services/pinpoint/model/SendUsersMessageResponse.java