Function class 

pub fn class(name: &str, opts: &Emit) -> String

A prefixed class name.

Public since 0.27.0, for the renderers that emit markup this crate does not. A screen renderer writing class="row" has to prefix it the way the stylesheet half does or a prefixed app gets rules matching everything except the elements that renderer wrote, and the failure is invisible: the CSS stays valid and one element is unstyled. quasi-webview carried a byte identical copy of this function until it could call this one.