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: scrape.rs
    path of file: ./repos/vector/src/sources/prometheus
    
    the code of the file until where you have to start completion: use std::collections::HashMap;
use std::time::Duration;

use bytes::Bytes;
use futures_util::Fut
    
    fn on_response(&mut self, url: &Uri, _header: &Parts, body: &Bytes) -> Option<Vec<Event>> {
        let body = String::from_utf8_lossy(body);

        match parser::parse_text(&body) {
            Ok(events) => Some(events),
            Err(error) => {
                if url.path() == "/" {
                    // https://github.com/vectordotdev/vector/pull/3801#issuecomment-700723178
                    warn!(
                        message = PARSE_ERROR_NO_PATH,
                        endpoint = %url,
                    );
                }
                emit!(PrometheusParseError {
                    error,
                    url: url.clone(),
                    body,
                });
                None
            }
        }
    }