// BinaryExpressionHelper.cs
public static void OnGetArguments<TLeft, TRight>(CodeActivityMetadata, InArgument<TLeft>, InArgument<TRight>);
public static void OnGetArguments<TLeft, TRight>(CodeActivityMetadata, InOutArgument<TLeft>, InArgument<TRight>);
public static void OnGetArguments<TLeft, TRight>(CodeActiviytMetadata, InArgument<TLeft, InOutArgument<TRight>);
public static void OnGetArguments<TLeft, TRight>(CodeActiviytMetadata, InOutArgument<TLeft, InOutArgument<TRight>);

// All of these forward to this method:
internal static void OnGetArgumentsBase<TLeft, TRight>
(
    CodeActivityMetadata,
    Argument left,
    ArgumentDirection leftDirection,
    Argument right,
    ArgumentDirection rightDirection
);