src/ holds zero observable-to-Task bridges, and a ratchet keeps it there

Bridging an observable to a Task completes that Task from inside the Rx pipeline, without RunContinuationsAsynchronously — so the awaiting code resumes inline, on the signalling thread, still inside Rx's trampoline, and everything it then calls inherits that. It is how a grain teardown came to park the very scheduler its own deactivation needed, and how a live children listing came to sit empty forever with no error and no completion.

Every such bridge is now gone from src/, tools/, samples/ and clients/. Waits that must still produce a Task — an ASP.NET endpoint, a silo lifecycle hook, the I/O pool's own reactive-leaf adapter — go through ReactiveCompletion.ObserveCompletion, which queues the caller's continuation instead of running it on the producer's thread and keeps its error arm attached so a late fault is reported rather than orphaned.

The shared test helpers moved with them: the request/response wait the whole suite runs (MonolithMeshTestBase.AwaitResponseAsync), the fluent stream assertions, the permission waits and the storage-adapter helpers. The old guidance said tests were the one sanctioned place to bridge; that was never true, because an assertion is the last thing a test awaits before it tears the mesh down, so the scheduler it resumes on is the scheduler the teardown runs on.

A new guard holds the line: src/ and friends are at zero with no allow-list at all, while the trees still being swept carry an inventory that may only shrink. The full account — what to write at each kind of boundary, the conversion traps, and how the guard proves it is not passing on an empty scan — is in Removing Observable-to-Task Bridges.