In which package or library can I fine the "StatefulContext" class?

I am trying to use EasyFlow for my project, but I am facing a problem, because I cannot find out from which package comes the "StatefulContext" class.

This class appears to be founmental, because all the "FlowConntext" should extend the "StatefulContext" class.

In case you know where I can find the "StatefulContext", please leave a comment below.