/// <summary>
/// Register UDF with 2 input arguments, e.g:
/// <see cref="SqlContext.RegisterFunction{bool, string, string}"/>("MyFilter", (arg1, arg2) => arg1 != null && arg2 != null);
/// sqlContext.Sql("SELECT * FROM MyTable where MyFilter(columnName1, columnName2)");
/// </summary>
/// <typeparam name="RT"></typeparam>
/// <typeparam name="A1"></typeparam>
/// <typeparam name="A2"></typeparam>
/// <param name="name"></param>
/// <param name="f"></param>
public void RegisterFunction <RT, A1, A2>(string name, Func <A1, A2, RT> f)
{
Func <int, IEnumerable <dynamic>, IEnumerable <dynamic> > udfHelper = new UdfHelper <RT, A1, A2>(f).Execute;
sqlContextProxy.RegisterFunction(name, SparkContext.BuildCommand(new CSharpWorkerFunc(udfHelper), SerializedMode.Row, SerializedMode.Row), Functions.GetReturnType(typeof(RT)));
}