         return result
     }
     
+    @discardableResult
     public func wait(wallDeadline: DispatchWallTime, qos: DispatchQoS = .unspecified, flags: DispatchWorkItemFlags = []) -> SDTask<Result?> {
         return self.wait(queue: queue, wallDeadline: wallDeadline, qos: qos, flags: flags)
     }
     
+    @discardableResult
     public func wait(queue: DispatchQueue, wallDeadline: DispatchWallTime, qos: DispatchQoS = .unspecified, flags: DispatchWorkItemFlags = []) -> SDTask<Result?> {
         var storage: Result?
         let result = SDTask<Result?>(queue: queue)

                _self.lck.broadcast()
            }
        }
    }
}


    private init(queue: DispatchQueue) {
        self.queue = queue
    }
}

extension SDTask {
