Please return to the error code when `catch`

[iwangx]

Thank you guys for bringing us such a good tool, but I hope that some places can be improved. When I entered catch, I found that no standard statusCode returned when there was no network and canceled requests, so I hoped that if it was a HTTP error, it would return the error code of the HTTP error, if it was to cancel a request and return a statusCode to distinguish what was wrong, thank you guys, most. Good blessings.

For example

RNFetchBlob.fetch("GET","http://test.test",{},{})
    .catch(function(err,statusCode){
        //I hope that the `statusCode` here returns every time and returns the wrong code according to the different errors.
    })