ユーザーのアバターを取得

curl -X GET https://api.box.com/2.0/users/12345/avatar \
     -H 'Authorization: Bearer <ACCESS_TOKEN>'

Stream imageStream = await client.UsersManager.GetUserAvatar(string userId);

String userID = "33333";
BoxUser user = new BoxUser(api, userID);
InputStream avatarStream = user.getAvatar();

avatar = client.user('33333').get_avatar()

client.users.getAvatar('22222')
    .then(avatarImageStream => {

        avatarImageStream.on('data', bytes => {
            // read avatar image bytes
        });
    });

client.users.getAvatar(userId: "33333") { (result: Result<Data, BoxSDKError>) in
    guard case let .success(avatarData) = result else {
        print("Error getting user avatar")
        return
    }

    let avatarImage = UIImage(data: avatarData)
}