You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: offscreen.rs
    path of file: ./repos/niri/src/render_helpers
    
    the code of the file until where you have to start completion: use smithay::backend::allocator::Fourcc;
use smithay::backend::renderer::element::solid::{Sol
    
    fn underlying_storage(&self, renderer: &mut GlesRenderer) -> Option<UnderlyingStorage> {
        if let Some(texture) = &self.texture {
            texture.underlying_storage(renderer)
        } else {
            self.fallback.underlying_storage(renderer)
        }
    }