As was already noted in a comment in the PlanningOracle declaration, the
PlanningOracle API is an exported entrypoint usable from outside lang/eval
and so each exported method should establish its own workgraph worker to
make sure it's handling those concerns correctly regardless of how the
caller chooses to use them.
For example, a caller might choose to make concurrent calls into the oracle
from multiple goroutines, which would violate the assumption that each
concurrently-running codepath is associated with a separate workgraph
worker.
Even if a caller is managing their own workgraph workers in the expected
way, this is functionally harmless and relatively cheap.
Signed-off-by: Martin Atkins <mart@degeneration.co.uk>
eb1d686806