BlobSampler API has become broken which lays a trap for the user. #426
Description
The BlobSampler API was broken by the addition of the aux PC.
- Only the "stepped" sampler fills it
- PointTreeBuilding assumes it exists
- Various clustering functions assume its contents
Use of any other live sampler will crash PTB. Protecting PTB just pushes the problem onto the downstream clustering functions.
Proper fix would be to break out this breakage and satisfy the need in some other way.
A lesser fix is to assure all samplers provide the required data in aux.
A naive user WILL experience problems if they get creative in what "live" sampler they configure to use. It is perfectly reasonable for them to do that kind of experimentation while this BlobSampler API breakage has layed a trap.