The Service should keep track of which Tasks it has sent to which Providers

[Kaliahh]

Is your feature request related to a problem? Please describe.
If a Provider crashes while working on a Task, that Task should be sent to another Provider if the original Provider no longer sends heartbearts.

It would also be a problem if the Service sent the same Task to two different Providers (When Byzantine is not selected)

Describe the solution you'd like
The Service should keep a log of which Tasks it has sent to which Provider