offload initial iterator seeks to threadpool

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

src/database/map/keys_prefix.rs

@@ -1,4 +1,4 @@
-use std::{convert::AsRef, fmt::Debug};
+use std::{convert::AsRef, fmt::Debug, sync::Arc};
 
 use conduit::{implement, Result};
 use futures::{
@@ -11,7 +11,7 @@ use serde::{Deserialize, Serialize};
 use crate::keyval::{result_deserialize_key, serialize_key, Key};
 
 #[implement(super::Map)]
-pub fn keys_prefix<'a, K, P>(&'a self, prefix: &P) -> impl Stream<Item = Result<Key<'_, K>>> + Send
+pub fn keys_prefix<'a, K, P>(self: &'a Arc<Self>, prefix: &P) -> impl Stream<Item = Result<Key<'_, K>>> + Send
 where
 	P: Serialize + ?Sized + Debug,
 	K: Deserialize<'a> + Send,
@@ -22,7 +22,7 @@ where
 
 #[implement(super::Map)]
 #[tracing::instrument(skip(self), level = "trace")]
-pub fn keys_prefix_raw<P>(&self, prefix: &P) -> impl Stream<Item = Result<Key<'_>>> + Send
+pub fn keys_prefix_raw<P>(self: &Arc<Self>, prefix: &P) -> impl Stream<Item = Result<Key<'_>>> + Send
 where
 	P: Serialize + ?Sized + Debug,
 {
@@ -32,7 +32,9 @@ where
 }
 
 #[implement(super::Map)]
-pub fn keys_raw_prefix<'a, K, P>(&'a self, prefix: &'a P) -> impl Stream<Item = Result<Key<'_, K>>> + Send + 'a
+pub fn keys_raw_prefix<'a, K, P>(
+	self: &'a Arc<Self>, prefix: &'a P,
+) -> impl Stream<Item = Result<Key<'_, K>>> + Send + 'a
 where
 	P: AsRef<[u8]> + ?Sized + Debug + Sync + 'a,
 	K: Deserialize<'a> + Send + 'a,
@@ -42,7 +44,7 @@ where
 }
 
 #[implement(super::Map)]
-pub fn raw_keys_prefix<'a, P>(&'a self, prefix: &'a P) -> impl Stream<Item = Result<Key<'_>>> + Send + 'a
+pub fn raw_keys_prefix<'a, P>(self: &'a Arc<Self>, prefix: &'a P) -> impl Stream<Item = Result<Key<'_>>> + Send + 'a
 where
 	P: AsRef<[u8]> + ?Sized + Debug + Sync + 'a,
 {