Convert Image Blur to Metal

I have a simple Objective C function that I would like to convert to use metal instead, for better performance. I have scoured the internet but can't seem to find much other than swift examples. How can I convert this code to metal for a quick image blur?

// Create our blurred image

CIContext *context = [CIContext contextWithOptions:nil];

CIImage *inputImage = [CIImage imageWithCGImage:thisImage.CGImage];

// Setting up Gaussian Blur

CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur"];

[filter setValue:inputImage forKey:kCIInputImageKey];

[filter setValue:[NSNumber numberWithFloat:5.0f] forKey:@"inputRadius"];

CIImage *result = [filter valueForKey:kCIOutputImageKey];

CGImageRef cgImage = [context createCGImage:result fromRect:[inputImage extent]];

UIImage *retVal = [UIImage imageWithCGImage:cgImage];

if (cgImage) {

CGImageRelease(cgImage);

}

return retVal;