Add string-consuming writer to admin context interface.

Signed-off-by: Jason Volk <jason@zemos.net>

src/admin/context.rs

@@ -23,14 +23,12 @@ impl Context<'_> {
 		arguments: fmt::Arguments<'_>,
 	) -> impl Future<Output = Result> + Send + '_ + use<'_> {
 		let buf = format!("{arguments}");
-		self.output.lock().then(async move |mut output| {
+		self.write_string(buf)
-			output
-				.write_all(buf.as_bytes())
-				.map_err(Into::into)
-				.await
-		})
 	}
 
+	#[inline]
+	pub(crate) async fn write_string(&self, s: String) -> Result { self.write_str(&s).await }
+
 	pub(crate) fn write_str<'a>(
 		&'a self,
 		s: &'a str,