Behind C# 6 string interpolation and how to customize it

In a search to find if my C# 6.0 code can target .Net 4.5, I’ve found an interesting post about string interpolation internals and how to customize it. For example, a custom IFormatProvider can be used to Uri.EscapeDataString interpoled strings.

Source: Customizing string interpolation in C# 6 » Thomas Levesque’s .NET blog

Apparently, MSDN’s documentation about FormattableString Class is wrong: FormattableString is only .Net 4.6 and not .Net 4.5 stuff.