使用NSProxy的时候遇到问题了

我在使用NSProxy替换NSURLSession原来的的delegate的时候，再使用AFNetwork的AFHTTPSessionManager的GET方法的时候崩溃了，不知道是什么原因，具体代码如下：

static void swizzleClassMethod(Class theClass, SEL originalSelector, SEL swizzledSelector)
{
Method origMethod = class_getClassMethod(theClass, originalSelector);
Method newMethod = class_getClassMethod(theClass, swizzledSelector);

theClass = object_getClass((id)theClass);

if(class_addMethod(theClass, originalSelector, method_getImplementation(newMethod), method_getTypeEncoding(newMethod)))
class_replaceMethod(theClass, swizzledSelector, method_getImplementation(origMethod), method_getTypeEncoding(origMethod));
else
method_exchangeImplementations(origMethod, newMethod);

}

@interface NSURLSession()

@property(nonatomic, strong) NSURLDelegateProxy *delegateProxy;

@end;

@implementation NSURLSession (DelegateMonitor)

+ (void)load {

static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
swizzleClassMethod([self class],
@selector(sessionWithConfiguration:delegate:delegateQueue:),
@selector(hcz_sessionWithConfiguration:delegate:delegateQueue:));
});

}

+ (NSURLSession *)hcz_sessionWithConfiguration:(NSURLSessionConfiguration *)configuration delegate:(nullable id )delegate delegateQueue:(nullable NSOperationQueue *)queue
{
if (delegate) {
NSURLDelegateProxy *proxy = [[NSURLDelegateProxy alloc] initWithTarget:delegate];
NSURLSession *session = [NSURLSession hcz_sessionWithConfiguration:configuration delegate:proxy delegateQueue:queue];

session.delegateProxy = proxy;

return session;
}


return [self hcz_sessionWithConfiguration:configuration delegate:delegate delegateQueue:queue];
}

@end

@interface NSURLDelegateProxy()
@property(nonatomic, weak) id proxyTarget;

@end

@implementation NSURLDelegateProxy

- (instancetype)initWithTarget:(id)target
{
self.proxyTarget = target;
return self;
}

- (void)forwardInvocation:(NSInvocation *)invocation
{
SEL sel = [invocation selector];
if ( [self.proxyTarget respondsToSelector:sel]) {
[invocation invokeWithTarget:self.proxyTarget];
}

}

- (nullable NSMethodSignature *)methodSignatureForSelector:(SEL)sel
{

NSMethodSignature *methodSignature = nil;

if ( [self.proxyTarget respondsToSelector:sel]) {
methodSignature = [self.proxyTarget methodSignatureForSelector:sel];
}

return methodSignature;
}

都是很简单的调用，AFHTTPSessionManager的调用方法如下：

AFHTTPSessionManager *session = [AFHTTPSessionManager manager];
NSURLSessionDataTask *task = [session GET:@"https://hcz-static.pingan.com.cn/fuelCard/fuelCard.zip" parameters:nil success:^(NSURLSessionDataTask * _Nonnull task, id _Nonnull responseObject) {

} failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {

}];

错误提示：
2017-12-08 18:08:44.923871+0800 AFNetworkingDemo[82876:14788953] *** NSForwarding: warning: object 0x608000036560 of class '__NSMessageBuilder' does not implement doesNotRecognizeSelector: -- abort