onProgress for FormData file upload

[rasumo]

onProgress for FormData file upload

[wendux]

Sorry, because dio depends on dart HttpClient, but it doesn't seem to exists any ways to retrieve upload progress. so...

[fvisticot]

Any progress on this,really need upload progress info !

[Xgamefactory]

it is possible to add stream to http package would be nice to add stream support for dio too

Stream<List<int>> streamUpload = msStream.transform(
      new StreamTransformer.fromHandlers(
        handleData: (data, sink) {
          sink.add(data);

          byteCount += data.length;

          if (onUploadProgress != null) {
            onUploadProgress(byteCount, totalByteLength);
            // CALL STATUS CALLBACK;
          }
        },
        handleError: (error, stack, sink) {
          throw error;
        },
        handleDone: (sink) {
          sink.close();
          // UPLOAD DONE;
        },
      ),
    );

    await request.addStream(streamUpload);