let mut posts: BTreeMap<DateTime<chrono::FixedOffset>, Post> = BTreeMap::new();

		let mut builder = self.http_client.get(&source.url);
		if let Some(last_scrape) = last_scrape {
			builder = builder.header(LAST_MODIFIED, last_scrape.to_rfc2822());
		};
		let response = builder.send().await.stack()?;

		// Print debug output for each response processed to track how expires
		// are handled
		#[cfg(debug_assertions)] {
			use reqwest::header::{
				EXPIRES,
				CACHE_CONTROL,
			};

			let headers = response.headers();
			let expires = headers.get(EXPIRES);
			let cache = headers.get(CACHE_CONTROL);
			if expires.is_some() || cache.is_some() {
				println!("{} {} {:?} {:?} {:?}", Local::now().to_rfc2822(), source.url, last_scrape, expires, cache);
		}	}

		let status = response.status();
		let content = response.bytes().await.stack()?;
		match rss::Channel::read_from(&content[..]) {
			Ok(feed) => {
				for item in feed.items() {
					if let Some(link) = item.link() {
						let date = match item.pub_date() {