Handle errors thrown while doing a DevFS sync via HTTP PUT. (#6434)

packages/flutter_tools/lib/src/devfs.dart

@@ -222,6 +222,7 @@ class _DevFSHttpWriter {
 
   Future<Null> _scheduleWrite(DevFSEntry entry,
                               DevFSProgressReporter progressReporter) async {
+    try {
       HttpClientRequest request = await _client.putUrl(httpAddress);
       request.headers.removeAll(HttpHeaders.ACCEPT_ENCODING);
       request.headers.add('dev_fs_name', fsName);
@@ -231,6 +232,9 @@ class _DevFSHttpWriter {
       await request.addStream(contents);
       HttpClientResponse response = await request.close();
       await response.drain();
+    } catch (e, stackTrace) {
+      printError('Error writing "${entry.devicePath}" to DevFS: $e\n$stackTrace');
+    }
     if (progressReporter != null) {
       _done++;
       progressReporter(_done, _max);