Replies to asynchronous requests can be retrieved by using
callbacks or reply solicitation calls.
Callbacks
ECIRequest supports callback objects. A callback object, which must implement
the Callbackable interface, receives the results of
the flow via the setResults method. When the results have been applied, a
new thread is started to execute the run method.
Reply solicitation calls
You can retrieve asynchronous replies using message qualifiers
and reply solicitation calls.