Xamarin Dropbox

• https://www.dropboxforum.com/t5/API-Support-Feedback/OAuth2-0-throws-invalid-grant-type-message-while-fetching-the/td-p/268801
• https://trevorhartsblog.com/2018/03/05/xamarin-android-dropbox-api-v2/
• https://www.dropboxforum.com/t5/API-Support-Feedback/How-do-I-set-the-Redirect-URI-port-number/td-p/243556
• https://stackoverflow.com/questions/41525569/xamarin-equivalent-to-webauthenticationbroker-getcurrentapplicationcallbackuri
• https://github.com/dropbox/dropbox-sdk-dotnet