The new IdeBuildPipeline provides a pluggable pipeline with phases. Stages
are attached within a given stage. When the pipeline is executed, it tries
to avoid performing unnecessary work so that we can speed up the rate at
which some user-actions can be performed (such as running).

You can invalidate phases for which those stages will need to be
re-executed next time the pipeline advances to that phase.

Stages can override some of this behavior by attaching to the ::query
signal to determine their "completed" status. If work needs to be
performed asynchronously, it can put a "hold" on the stage and release
the hold after the asynchronous work is completed. The pipeline will
pause to wait for thie operation to complete.

You likely want to use some of the pre-created build stage subclasses
such as for creating directories, launching subprocesses, or performing
transfers.