Improve performance of HighLevelGraph construction (#6293)
Improve performance of HighLevelGraph construction (#6293)

* Add a from_collection classmethod to simplify single dependency case

* Forgot name in layers

* Create non HLG deps set properly

* Make from_collection a private method

* Forgot to rename in call
blaze/dask,dask/dask,jakirkham/dask,dask/dask,jakirkham/dask,mrocklin/dask,mrocklin/dask,blaze/dask,ContinuumIO/dask,ContinuumIO/dask