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: gen_GpuImageCopyBuffer.rs
    path of file: ./repos/wgpu/wgpu/src/backend/webgpu/webgpu_sys
    
    the code of the file until where you have to start completion: // DO NOT EDIT THIS FILE!
//
// This module part of a subset of web-sys that is used by wgpu's webgpu backend.
//
// If you want to improve the generated code, please submit a PR to the https://github.com/rustw
    
    pub fn buffer(&mut self, val: &GpuBuffer) -> &mut Self {
        use wasm_bindgen::JsValue;
        let r =
            ::js_sys::Reflect::set(self.as_ref(), &JsValue::from("buffer"), &JsValue::from(val));
        debug_assert!(
            r.is_ok(),
            "setting properties should never fail on our dictionary objects"
        );
        let _ = r;
        self
    }