code: func Copy(ctx context.Context) context.Context {
  	return CopyToContext(context.Background(), ctx)
  }
docs: // Copy copies common httpx values injected into a request context to another
  // context.
  //
  // This is useful when performing work outside of the request lifecycle that was
  // a result of a request. For instance, the request id and tracing spans are useful
  // but the deadline of the request context does not apply.