wip: abort rust connections if early abort detected

Author: stevensJourney

.changeset/honest-penguins-worry.md

@@ -0,0 +1,5 @@
+---
+'@powersync/common': patch
+---
+
+Fix issue where Rust sync implementation might not disconnect in some circumstances.

packages/common/src/client/sync/stream/AbstractStreamingSyncImplementation.ts

@@ -899,6 +899,9 @@ The next upload iteration will be delayed.`);
     let receivingLines: Promise<void> | null = null;
     let hadSyncLine = false;
 
+    if (signal.aborted) {
+      return;
+    }
     const abortController = new AbortController();
     signal.addEventListener('abort', () => abortController.abort());