Indicates that method is used to retrieve current workflow state. The method
is expected to perform read only access of the workflow implementation object
and is invoked synchronously which disallows use of any asynchronous
operations (like calling methods annotated with
Method is expected to have empty list of parameters.
return types are not allowed for the annotated method.
The generated external client implementation uses
visibility API to retrieve the state. It allows access to the sate using external client if decider
workers are down and even after workflow execution completion.
@author fateev, samar