iOS CMSampleBuffer deep copy

extension CVPixelBuffer {
func copy() -> CVPixelBuffer {
precondition(CFGetTypeID(self) == CVPixelBufferGetTypeID(), "copy() cannot be called on a non-CVPixelBuffer")

var _copy : CVPixelBuffer?

//        var BytesAlignment:Int = 4
//        let CFBytesAlignment = CFNumberCreate(kCFAllocatorDefault, .intType, &BytesAlignment)!
let attribute:[String:Any] = [kCVPixelBufferMetalCompatibilityKey as String:kCFBooleanTrue]
//                                      kCVPixelBufferBytesPerRowAlignmentKey as String:CFBytesAlignment

CVPixelBufferCreate(
kCFAllocatorDefault,
CVPixelBufferGetWidth(self),
CVPixelBufferGetHeight(self),
CVPixelBufferGetPixelFormatType(self),
attribute as CFDictionary,
&_copy)

guard let copy = _copy else { fatalError() }

CVPixelBufferLockBaseAddress(self, CVPixelBufferLockFlags.readOnly)
CVPixelBufferLockBaseAddress(copy, CVPixelBufferLockFlags(rawValue: 0))

for plane in 0..<CVPixelBufferGetPlaneCount(self) {
let dest = CVPixelBufferGetBaseAddressOfPlane(copy, plane)
let source = CVPixelBufferGetBaseAddressOfPlane(self, plane)
let height = CVPixelBufferGetHeightOfPlane(self, plane)
let bytesPerRow = CVPixelBufferGetBytesPerRowOfPlane(self, plane)

let bytesPerRowDst = CVPixelBufferGetBytesPerRowOfPlane(copy, plane)

for h in 0..<height {
memcpy(dest?.advanced(by:h*bytesPerRowDst), source?.advanced(by:h*bytesPerRow),  bytesPerRow)
}
}

CVPixelBufferUnlockBaseAddress(copy, CVPixelBufferLockFlags(rawValue: 0))
CVPixelBufferUnlockBaseAddress(self, CVPixelBufferLockFlags.readOnly)

return copy
}
}