WIP: Fused Continuation- and Completion-Stealing

emper/Runtime.cpp

@@ -433,6 +433,7 @@ auto Runtime::nextFiber() -> std::optional<NextFiberResult> {
 		IoContext::ContinuationBuffer completions;
 		unsigned ncompletions =
 				IoContext::getWorkerIo()->reapCompletions<CallerEnvironment::OWNER>(completions);
+		// TODO: "Sort" completions by ones we want to defer and ones we want to execute right away.
 		if (ncompletions > 0) {
 			// Keep the first and schedule the rest
 			Fiber* next = completions[0];