message: Improve readability of ExternalQuerier.query
diff: @@ -245,21 +245,21 @@ impl Querier for ExternalQuerier {
  fn query(&self, request: &QueryRequest) -> QuerierResponse {
  let bin_request = to_vec(request).or(Err(ApiSystemError::Unknown {}))?;
  let req = build_region(&bin_request);
  - let req_ptr = &*req as *const Region as *const c_void;
  - let resp = alloc(QUERY_RESULT_BUFFER_LENGTH);
  + let request_ptr = &*req as *const Region as *const c_void;
  + let response_ptr = alloc(QUERY_RESULT_BUFFER_LENGTH);
  - let ret = unsafe { query_chain(req_ptr, resp) };
  - if ret < 0 {
  + let result_code = unsafe { query_chain(request_ptr, response_ptr) };
  + if result_code < 0 {
  return Err(ApiSystemError::Unknown {});
  }
  - let parse = |r| -> StdResult<QuerierResponse> {
  - let out = unsafe { consume_region(r)? };
  + let process = |region_ptr| -> StdResult<QuerierResponse> {
  + let out = unsafe { consume_region(region_ptr)? };
  let parsed: ApiResult<ApiResult<Binary>, ApiSystemError> = from_slice(&out)?;
  Ok(parsed.into())
  };
  - match parse(resp) {
  + match process(response_ptr) {
  Ok(api_response) => api_response,
  Err(err) => Ok(Err(err.into())),
  }
  