uploading binary data causes expected dynamic type 'string', but had type 'object' error in Android

[haikyuu]

Thanks for your great work on this library.
I am using 0.10.8 and react-native 0.48.2.
I have an issue uploading binary data in Android.

RNFetchBlob.fetch("PUT",
    signedRequest, {
       "Content-Type": "application/octet-stream",
       body: {uri}
    },
  )

But i get this error

TypeError:expected dynamic type 'string', but had type 'object' (constructing arguments for RNFetchBlob.fetchBlob at argument index 3)

Any clues?