make scheduler accept multiple batch handlers

meilisearch-lib/src/dump/loaders/v1.rs

@@ -0,0 +1,24 @@
+use std::path::Path;
+
+use serde::{Deserialize, Serialize};
+
+use crate::index_controller::IndexMetadata;
+
+#[derive(Serialize, Deserialize, Debug)]
+#[serde(rename_all = "camelCase")]
+pub struct MetadataV1 {
+    pub db_version: String,
+    indexes: Vec<IndexMetadata>,
+}
+
+impl MetadataV1 {
+    #[allow(dead_code, unreachable_code, unused_variables)]
+    pub fn load_dump(
+        self,
+        src: impl AsRef<Path>,
+        dst: impl AsRef<Path>,
+        size: usize,
+        indexer_options: &IndexerOpts,
+    ) -> anyhow::Result<()> {
+        anyhow::bail!("The version 1 of the dumps is not supported anymore. You can re-export your dump from a version between 0.21 and 0.24, or start fresh from a version 0.25 onwards.")
+}