func withUnsafeMutableBytes<T, Result>(of: inout T, _: (UnsafeMutableRawBufferPointer) throws -> Result) Invokes the given closure with a mutable buffer pointer covering the raw bytes of the given argument. The buffer pointer argument to the body closure provides a collection interface to the raw bytes of arg. The buffer is the size of the instance passed as arg and does not include any remote storage. Parameters: arg: An instance to temporarily access through a mutable raw buffer pointer. body: A closure that takes a raw buffer pointer to the bytes of arg as its sole argument. If the closure has a return value, it is used as the return value of the withUnsafeMutableBytes(of:_:) function. The buffer pointer argument is valid only for the duration of the closure's execution. Returns: The return value of the body closure, if any. See Also: withUnsafeMutablePointer(to:_:), withUnsafeBytes(of:_:) Declaration func withUnsafeMutableBytes<T, Result>(of arg: inout T, _ body: (UnsafeMutableRawBufferPointer) throws -> Result) rethrows -> Result