offload initial iterator seeks to threadpool

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

src/database/map/keys.rs

@@ -2,7 +2,7 @@ use conduit::{implement, Result};
 use futures::{Stream, StreamExt};
 use serde::Deserialize;
 
-use crate::{keyval, keyval::Key, stream};
+use crate::{keyval, keyval::Key, stream, stream::Cursor};
 
 #[implement(super::Map)]
 pub fn keys<'a, K>(&'a self) -> impl Stream<Item = Result<Key<'_, K>>> + Send
@@ -16,5 +16,5 @@ where
 #[tracing::instrument(skip(self), fields(%self), level = "trace")]
 pub fn raw_keys(&self) -> impl Stream<Item = Result<Key<'_>>> + Send {
 	let opts = super::read_options_default();
-	stream::Keys::new(&self.db, &self.cf, opts, None)
+	stream::Keys::new(&self.db, &self.cf, opts).init(None)
 }