You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: iunknown.go
    path of file: ./repos/sliver/vendor/github.com/Ne0nd0g/go-clr
    
    the code of the file until where you have to start completion: // +build windows

package clr

import (
	"fmt"
	"syscall"
    
func (obj *IUnknown) AddRef() (count uint32, err error) {
	debugPrint("Entering into iunknown.AddRef()...")
	ret, _, err := syscall.Syscall(
		obj.vtbl.AddRef,
		1,
		uintptr(unsafe.Pointer(obj)),
		0,
		0,
	)
	if err != syscall.Errno(0) {
		return 0, fmt.Errorf("the IUnknown::AddRef method returned an error:\r\n%s", err)
	}
	err = nil
	// Unable to avoid misuse of unsafe.Pointer because the Windows API call returns the safeArray pointer in the "ret" value. This is a go vet false positive
	count = *(*uint32)(unsafe.Pointer(ret))
	return
}