code: func (h Hash) Size() int {
  	if h > 0 && h < maxHash {
  		return int(digestSizes[h])
  	}
  	panic("crypto: Size of unknown hash function")
  }
docs: // Size returns the length, in bytes, of a digest resulting from the given hash
  // function. It doesn't require that the hash function in question be linked
  // into the program.