pub trait GLAreaImpl: GLAreaImplExt + WidgetImpl {
fn create_context(&self, gl_area: &Self::Type) -> Option<GLContext> { ... }
fn render(&self, gl_area: &Self::Type, context: &GLContext) -> bool { ... }
fn resize(&self, gl_area: &Self::Type, width: i32, height: i32) { ... }
}