The seven states of a piece of work Diagram

Four kinds of state

With someone: With worker or With supervisor
Handed off: to supervisor, to worker or to a named target
On hold, and Finished

Only two things are set

The receive words are with me, ack, got it and seen; pause and done for now agree a hold; resume and finish are the moves off hold
The supervisor's receive and the hold are set
Every other state is derived from where the work's items lie
A heartbeat runs only while work lies with a worker

On hold has two reasons

Paused: waiting on a named release condition while other work goes on
More expected: done for now, released when new work arrives
Drain is the activity on the way in, never a state