BoxKite.Twitter.FriendsFollowersExtensions.GetFriendship C# (CSharp) Метод

        public async static Task<UserStatus> GetFriendship(this IUserSession session, string sourceScreenName="",string targetScreenName="", int sourceId=0,int targetId=0)
        {
            var parameters = new TwitterParametersCollection();

            if (!string.IsNullOrWhiteSpace(sourceScreenName))
            {
                parameters.Add("source_screen_name", sourceScreenName);
            }

            if (sourceId != 0)
            {
                parameters.Add("source_id", sourceId.ToString());
            }

            if (!string.IsNullOrWhiteSpace(targetScreenName))
            {
                parameters.Add("target_screen_name", targetScreenName);
            }

            if (targetId != 0)
            {
                parameters.Add("target_id", targetId.ToString());
            }

            if (parameters.EnsureAllArePresent(new [] { "source_screen_name", "source_id", "target_screen_name", "target_id" }).IsFalse())
            {
                return session.MapParameterError<UserStatus>(
                        "source_screen_name, source_id, target_screen_name and target_id are all required");
            }


            return await session.PostAsync(TwitterApi.Resolve("/1.1/friendships/show.json"), parameters)
                          .ContinueWith(c => c.MapToSingle<UserStatus>());
        }