iOS CFNetworking NetworkProxy memory leak

iOS 9.2 use NSURLCoection

vastNetCoect = [[NSURLCoection alloc] initWithRequest:request delegate:self startImmediately:NO];

[vastNetCoect scheduleInRunLoop:[NSRunLoop mainRunLoop]
                      forMode:NSDefaultRunLoopMode];
[vastNetCoect start];
if (self.delegate && [self.delegate respondsToSelector:@selector(startGetData:)]) {
    [self.delegate startGetData:self];
}

use instrument check memory leak

anyone has good idea how to solve this problem ? is it system problem ?