Is IReadOnlyDictionary supported as DictionarySource?

[dombrovsky]

Is your feature request related to a problem? Please describe.
If arguments for formatting are coming as IReadOnlyDictionary (not upcastable to IDictionary), there is no built in Source that can handle it.
,
Describe the solution you'd like
Should be a straightforward piece to add IReadOnlyDictionary support to DictionarySource, same way as it handles IDictionary.

Describe alternatives you've considered
Workaround is to convert IReadOnlyDictionary to IDictionary, but that would cause additional allocations.
There is always a possibility to implement custom Source on consumer side.

[axunonb]

You're saying that this tests fails for SmartFormat v3.2.1?

[Test]
public void ReadOnlyDictionaryTest()
{
    var dict = new Dictionary<string, object> { { "One", 1 }, { "Two", 2 }, { "Three", 3 }, };
    var roDict = new ReadOnlyDictionary<string, object>(dict);

    var formatter = Smart.CreateDefaultSmartFormat();
    var result = formatter.Format("{One}{Two}{Three}", roDict);

    Assert.That(result, Is.EqualTo("123"));
}