Interface onUploadBegin

android/src/main/java/com/rnfs/UploadParams.java:15–17

        void onUploadProgress(int totalBytesExpectedToSend,int totalBytesSent);
    }
    public interface onUploadBegin{
        void onUploadBegin();
    }
    public URL src;
    public ArrayList<ReadableMap> files;
    public boolean binaryStreamOnly;