Speed up tasks execution by eagerly calling scheduled callbacks (25-35% burst)

The ‘main’ branch runs callbacks scheduled by loop.call_soon() on the next event loop iteration. The proposed gh-160760: asyncio: run newly scheduled callbacks eagerly before polling for I/O by asvetlov · Pull Request #145149 · python/cpython · GitHub eagerly executes callbacks scheduled during a loop iteration in the same loop._run_once() call until one of the following conditions happens: Allowed time slot for eager callbacks execution timed out (100us by default). Allowed amount of eager c...