message: Add obj-c message forwarding to real object
diff: [super dealloc];
  }
  +// Use the real MTLFunction to find methods from messages
  +- (NSMethodSignature *)methodSignatureForSelector:(SEL)aSelector
  +{
  + id fwd = self.real;
  + return [fwd methodSignatureForSelector:aSelector];
  +}
  +
  +// Forward any unknown messages to the real MTLFunction
  +- (void)forwardInvocation:(NSInvocation *)invocation
  +{
  + SEL aSelector = [invocation selector];
  +
  + if([self.real respondsToSelector:aSelector])
  + [invocation invokeWithTarget:self.real];
  + else
  + [super forwardInvocation:invocation];
  +}
  +
  // MTLFunction : based on the protocol defined in
  // Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.1.sdk/System/Library/Frameworks/Metal.framework/Headers/MTLLibrrary.h
  