Flush on write in FileByteStore.

pkg/analyzer/lib/src/dart/analysis/file_byte_store.dart

Index: pkg/analyzer/lib/src/dart/analysis/file_byte_store.dart
diff --git a/pkg/analyzer/lib/src/dart/analysis/file_byte_store.dart b/pkg/analyzer/lib/src/dart/analysis/file_byte_store.dart
index fba6fbfb8af1516f845e95420894a019237c5c38..5b79b503bf684d411c490ba3029fb352d6e6f348 100644
--- a/pkg/analyzer/lib/src/dart/analysis/file_byte_store.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/file_byte_store.dart
@@ -159,7 +159,7 @@ class FileByteStore implements ByteStore {
   void put(String key, List<int> bytes) {
     try {
       File tempFile = _getFileForKey(_tempName);
-      tempFile.writeAsBytesSync(bytes);
+      tempFile.writeAsBytesSync(bytes, flush: true);
       File file = _getFileForKey(key);
       tempFile.renameSync(file.path);
     } catch (_) {}