A runtime implementation that runs everything on the current thread.
Arbiters provide an asynchronous execution environment for actors, functions and futures. When an Arbiter is created, they spawn a new OS thread, and host an event loop. Some Arbiter functions execute on the current thread.
Builder struct for a actix runtime.
Single-threaded runtime provides a way to start reactor and executor on the current thread.
System is a runtime manager.
Helper object that runs System's event loop
Spawns a future on the current arbiter.