pub fn index(&mut self) -> usize {
        let index = self.total;
        self.total += 1;
        index
    }
/// Gets the index of the field.
Gets the index of the field.
Gets the index of the field .
pub fn index(&mut self) -> usize {
        let index = self.total;
        self.total += 1;
        index
    }
pub fn index ( & mut self ) -> usize { let index = self . total ; self . total += 1 ; index }
Gets the index of the field.
Gets the index of the field .
&mut self
&mut self