Multi-task generator uses _id.

[shuds13]

ax_trial_id and arm_name are not shared externally.

Note: this generator sometimes fails to produce points when a suggest can be for more points than are in the buffer. To work reliably with libEnsemble, this should be able to generate more points to fill out the request. Created issue #295.

• Check in tests
• Check in examples
• Check in libEnsemble (using multitask gen). Including with a previous History read in.
• Lets add 'returns_id: bool = True' to other generators also in this branch. Check all that issue _id.
• Agree on _id policy for unknown points (do they get _id internally - increment _id or do new points start at 0).

When previous points are given as a history, these are added to the Ax experiment internally, and then procedes as if a new run (sobol phase).

Note, that when a history is read into gen, these points are allocated _ids internally.

So suggested points after that will provide _ids that do not start at zero.

[shuds13]

Do we want this, for unknown points.

[shuds13]

Could be used as a quick way to tell if covered sample, and dont need more sobol points.

Currently I just start a restart with sobol points.