Function ST_Buffer 

pub fn ST_Buffer<G: Into<Geometry>, g, d>(
    g: g,
    d: d,
) -> ST_Buffer<G, <g as AsExpression<G>>::Expression, <d as AsExpression<Double>>::Expression>
where
    g: AsExpression<G>,
    d: AsExpression<Double>,

Represents the MySQL ST_Buffer function (with two arguments)