/// <summary>
/// Returns a dictionary of key/value pairs for which request options
/// have been added to the existing set of filters.
/// </summary>
/// <param name="filter">
/// A <see cref="IEntityFilter"/> instance; an object which can be represented as a set of key/value pairs.
/// </param>
/// <param name="options">
/// A <see cref="RequestOptions"/> object for controlling the behavior of API calls.
/// </param>
/// <returns>The dictionary of concatenated key-value pairs.</returns>
internal static Dictionary <string, string> GetFiltersWithOptions(
this IEntityFilter filter,
RequestOptions options)
{
options.ThrowIfNull();
Dictionary <string, string> filters = filter.GetFilters();
Dictionary <string, string> optionsFilters = options.GetFilters();
return(filters.Concat(optionsFilters).ToDictionary(s => s.Key, s => s.Value));
}