Rearm the CFFileDescriptor before each CFRunLoop run.

Instead of rearming from within the callback, this enables the callback before the event loop is run and before the kqueue is cleared. This at least heavily reduces the cases where the CFRunLoop hangs instead of reporting a pending kqueue event. For this reason, the safety timeout has been increased to 5 seconds.

source/eventcore/drivers/posix/cfrunloop.d

@@ -31,7 +31,6 @@ final class CFRunLoopEventLoop : KqueueEventLoopBase {
 		m_kqueueDescriptor = CFFileDescriptorCreate(kCFAllocatorDefault,
 			m_queue, false, &processKqueue, &ctx);
 
-		CFFileDescriptorEnableCallBacks(m_kqueueDescriptor, CFOptionFlags.kCFFileDescriptorReadCallBack);
 		m_kqueueSource = CFFileDescriptorCreateRunLoopSource(kCFAllocatorDefault, m_kqueueDescriptor, 0);
 		CFRunLoopAddSource(CFRunLoopGetCurrent(), m_kqueueSource, kCFRunLoopDefaultMode);
 	}
@@ -40,6 +39,8 @@ final class CFRunLoopEventLoop : KqueueEventLoopBase {
 	@trusted {
 		import std.algorithm.comparison : min;
 
+		CFFileDescriptorEnableCallBacks(m_kqueueDescriptor, CFOptionFlags.kCFFileDescriptorReadCallBack);
+
 		// submit changes and process pending events
 		auto kres = doProcessEventsBase(0.seconds);
 		if (kres) timeout = 0.seconds;
@@ -55,14 +56,15 @@ final class CFRunLoopEventLoop : KqueueEventLoopBase {
 		//       events does not help (and is also eplicitly discouraged in
 		//       Apple's documentation).
 		while (timeout > 0.seconds) {
-			auto tol = min(timeout, 1.seconds);
+			auto tol = min(timeout, 5.seconds);
 			timeout -= tol;
 			CFTimeInterval to = 1e-7 * tol.total!"hnsecs";
 			auto res = CFRunLoopRunInMode(kCFRunLoopDefaultMode, to, true);
 			if (res != CFRunLoopRunResult.kCFRunLoopRunTimedOut) {
 				return kres || res == CFRunLoopRunResult.kCFRunLoopRunHandledSource;
 			}
 
+			CFFileDescriptorEnableCallBacks(m_kqueueDescriptor, CFOptionFlags.kCFFileDescriptorReadCallBack);
 			kres = doProcessEventsBase(0.seconds);
 			if (kres) break;
 		}
@@ -83,7 +85,6 @@ final class CFRunLoopEventLoop : KqueueEventLoopBase {
 		CFOptionFlags callBackTypes, void* info)
 	{
 		auto this_ = () @trusted { return cast(CFRunLoopEventLoop)info; } ();
-		auto res = this_.doProcessEventsBase(0.seconds);
-		() @trusted { CFFileDescriptorEnableCallBacks(this_.m_kqueueDescriptor, CFOptionFlags.kCFFileDescriptorReadCallBack); } ();
+		this_.doProcessEventsBase(0.seconds);
 	}
 }