StringEx.Format("{0}", "argument1")

// only register once
StringEx.RegisterFormatFunc("name", () => "PlayerNameA");

// after register
StringEx.Format("{name}")

// only register once
StringEx.RegisterFormatFunc("i18n", (index, parameters) => 
    {
        // TOOD load text from i18n config
        return $"i18n_content_({parameters[index]})";
    });

// after register
StringEx.Format("{0:i18n}", 1001)

var formatter1 = new StringFormatter.StringFormatter();
formatter1.RegisterFormatFunc("name", () => "name in context1");
            
var formatter2 = new StringFormatter.StringFormatter();
formatter2.RegisterFormatFunc("name", () => "name in context2");

// after register
formatter1.Format("{name}");
formatter2.Format("{name}");