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: mod.rs
    path of file: ./repos/smithay/src/backend/renderer
    
    the code of the file until where you have to start completion: //! Rendering functionality and abstractions
//!
//! Collection of common traits and implementations
//! to facilitate (possible hardware-accelerated) rendering.
//!
//! Supported rendering apis:
//!
//! - Raw OpenGL ES 2

use std::collections::HashSet;
use std::error::Error;
use std::fmt;

use crate::utils
    
pub fn buffer_y_inverted(buffer: &wl_buffer::WlBuffer) -> Option<bool> {
    if let Ok(dmabuf) = crate::wayland::dmabuf::get_dmabuf(buffer) {
        return Some(dmabuf.y_inverted());
    }

    #[cfg(all(feature = "backend_egl", feature = "use_system_lib"))]
    if let Some(Ok(egl_buffer)) = BUFFER_READER
        .lock()
        .unwrap()
        .as_ref()
        .and_then(|x| x.upgrade())
        .map(|x| x.egl_buffer_contents(buffer))
    {
        return Some(egl_buffer.y_inverted);
    }

    None
}