fn mainLoop(ev: *Evented, message: *const SwitchMessage) callconv(.c) noreturn
fn mainLoop(ev: *Evented, message: *const SwitchMessage) callconv(.c) noreturn { message.handle(ev); assert(ev.exit_semaphore.wait(.FOREVER) == 0); Fiber.@"resume"(&ev.main_fiber); unreachable; // switched to dead fiber }