public async Task<BoxUser> ChangeUsersLoginAsync(string userId, string login, List<string> fields = null)
{
userId.ThrowIfNullOrWhiteSpace("userId");
login.ThrowIfNullOrWhiteSpace("login");
BoxRequest request = new BoxRequest(_config.UserEndpointUri, userId)
.Param(ParamFields, fields)
.Payload(_converter.Serialize(new BoxUserRequest() { Login = login }))
.Method(RequestMethod.Put);
IBoxResponse<BoxUser> response = await ToResponseAsync<BoxUser>(request).ConfigureAwait(false);
return response.ResponseObject;
}