Prepare consistent Chunk sizes and fresh Fast Fetch integration

src/common/replicatorResources/index.ts

@@ -14,3 +14,4 @@ export {
     type SecuritySeedResourceHost,
 } from "./securitySeed";
 export { createCouchDBSynchronisationInformationResourceFactory } from "./synchronisationInformation";
+export { createCouchDBInitialFetchFastForwardResourceFactory } from "./initialFetchFastForward";

src/common/replicatorResources/initialFetchFastForward.ts

@@ -0,0 +1,17 @@
+import type { InitialFetchFastForwardResourceFactory } from "@vrtmrz/livesync-commonlib/replication";
+import {
+    LiveSyncCouchDBReplicator,
+    type LiveSyncCouchDBReplicatorEnv,
+} from "@vrtmrz/livesync-commonlib/compat/replication/couchdb/LiveSyncReplicator";
+import { snapshotRemoteSettings } from "./shared";
+
+/** Create a private CouchDB Replicator for a fresh Fast Fetch checkpoint handoff. */
+export function createCouchDBInitialFetchFastForwardResourceFactory(
+    host: LiveSyncCouchDBReplicatorEnv
+): InitialFetchFastForwardResourceFactory {
+    return (setting) => {
+        const snapshot = snapshotRemoteSettings(setting);
+        const replicator = new LiveSyncCouchDBReplicator(host);
+        return Promise.resolve(replicator.createInitialFetchFastForwardResource(snapshot));
+    };
+}