[pubsub-client] doctest loops indefinitely; contacts the internet

[steveluscher]

Consider this doctest:

agave/pubsub-client/src/pubsub_client.rs

Lines 47 to 87 in c59d2c1

	//! ```
	//! use anyhow::Result;
	//! use solana_commitment_config::CommitmentConfig;
	//! use solana_pubkey::Pubkey;
	//! use solana_pubsub_client::pubsub_client::PubsubClient;
	//! use solana_rpc_client_api::config::RpcAccountInfoConfig;
	//! use std::thread;
	//!
	//! fn get_account_updates(account_pubkey: Pubkey) -> Result<()> {
	//! let url = "wss://api.devnet.solana.com/";
	//!
	//! let (mut account_subscription_client, account_subscription_receiver) =
	//! PubsubClient::account_subscribe(
	//! url,
	//! &account_pubkey,
	//! Some(RpcAccountInfoConfig {
	//! encoding: None,
	//! data_slice: None,
	//! commitment: Some(CommitmentConfig::confirmed()),
	//! min_context_slot: None,
	//! }),
	//! )?;
	//!
	//! loop {
	//! match account_subscription_receiver.recv() {
	//! Ok(response) => {
	//! println!("account subscription response: {:?}", response);
	//! }
	//! Err(e) => {
	//! println!("account subscription error: {:?}", e);
	//! break;
	//! }
	//! }
	//! }
	//!
	//! Ok(())
	//! }
	//! #
	//! # get_account_updates(solana_pubkey::new_rand());
	//! # Ok::<(), anyhow::Error>(())
	//! ```

• Only ever times out after 60 seconds (slows down CI)
• Actually connects to api.devnet.solana.com (ergo will fail CI if that server is unreachable)