Watch clipboard for all content types and return a type with the content

[xiebruce]

I need to watch if the clipboard is changed at a time, and return the bytes with a type, so I can deal with it.

for now, I need do

textBytes, := clipboard.Watch(context.Background(), clipboard.FmtText)
imageBytes := clipboard.Watch(context.Background(), clipboard.FmtImage)

but I hope I can do this

clipBytes,contentType := clipboard.Watch(context.Background())

because we don't need to watch clipboard two times right?