Logical Xor for std.zh

//The most efficient Logical Xor function possible.
//Minimum statement evaluations (1)
//Maximum statement evaluations (3)
bool Xor(bool a, bool b)
{
     if ( a )
     {
          if ( !b ) return true;
     }
     else
     {
          if ( b ) return true;
     }
     return false;
}