Sending a FormData() as the body of a request with RNFetchBlob

Question

I have a problem with sending FormData() with RNFetchBlob.fetch(); I tried put external fields to array but it doesn't work

[{
    "name": 'some',
    "filename": filename,
    "data":RNFetchBlob.wrap(video.uri),
    'message': this.state.message,
    'event_id': id,
    'private': "false"
}]

How can I solve this issue ?