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: resolver.rs
    path of file: ./repos/reth/crates/net/dns/src
    
    the code of the file until where you have to start completion: //! Perform DNS lookups

use parking_lot::RwLock;
use std::{collections::HashMap, future::Future};
use tracing::trace;
pub use trust_dns_resolver::{error::ResolveError, TokioAsyncResolver};
use trust_dns_re
    
    async fn lookup_txt(&self, query: &str) -> Option<String> {
        // See: [AsyncResolver::txt_lookup]
        // > *hint* queries that end with a '.' are fully qualified names and are cheaper lookups
        let fqn = if query.ends_with('.') { query.to_string() } else { format!("{query}.") };
        match self.txt_lookup(fqn).await {
            Err(err) => {
                trace!(target: "disc::dns", %err, ?query, "dns lookup failed");
                None
            }
            Ok(lookup) => {
                let txt = lookup.into_iter().next()?;
                let entry = txt.iter().next()?;
                String::from_utf8(entry.to_vec()).ok()
            }
        }
    }