StartWorkflowOptions will get exisiting workflow or start a new one if DNE.

will get exisiting workflow or start a new one id DNE.

MockMutexLock stubs mutex.Lock call.

this one differes from NewWorkflow by supporting reference to itself (useful for w.NewContinueAsNewError).

primary clients will be used for creating new workflows on.

useful for migrating from one queue to the other put new worker/queue in primary and old ones in other newly created worfklow will be put in new queue old ones will continue to work until they are re-created.

use this to achieve better contract testing.