Experimental delegate support.

FSURLOperation.h

@@ -16,7 +16,8 @@
 @property (strong) NSError * error;
 @property (strong) NSThread* targetThread; // changing this after the request has started produces undefined behavior.
 @property (copy) void(^onFinish)(NSHTTPURLResponse* resp, NSData* payload, NSError* error);
-// todo: delegate based callbacks
+@property (weak) id delegate;
+@property (assign) SEL callback;
 
 + (FSURLOperation*)URLOperationWithRequest:(NSURLRequest*)req
                            completionBlock:(void(^)(NSHTTPURLResponse* resp, NSData* payload, NSError* error))completion;

FSURLOperation.m

@@ -34,6 +34,8 @@ @implementation FSURLOperation
 @synthesize error;
 @synthesize targetThread;
 @synthesize onFinish;
+@synthesize delegate;
+@synthesize callback;
 
 @synthesize state;
 @synthesize connection;
@@ -101,7 +103,16 @@ - (void)finish
     [self willChangeValueForKey:@"isFinished"];
     self.state = finished;
     if (self.onFinish) self.onFinish(self.response, self.payload, self.error);
-    // TODO: Delegate-based callbacks
+    if (self.delegate&&self.callback) {
+        NSInvocation* inv = [[NSInvocation alloc] init];
+        [inv setTarget:self.delegate];
+        [inv setSelector:self.callback];
+        [inv setArgument:(__bridge void*)self.response atIndex:2];
+        [inv setArgument:(__bridge void*)self.payload atIndex:3];
+        [inv setArgument:(__bridge void*)self.error atIndex:4];
+
+        [inv invoke];
+    }
     [self didChangeValueForKey:@"isFinished"];
 }