Unity3D Immutable Collections

A poor man's C# immutable collections in Unity.

This is an (incomplete) implementation of the standard immutable collections library using the existing collections found in .NET 2.0. Some of the API is changed to fit in the old framework. For instance ImmutableDictionarie has only a (key) compararer as dictionaries do not support value compararers.

Some code borrowed from .NET Core foundational libraries: https://github.com/dotnet/corefx/blob/master/src/System.Collections.Immutable

Notes on performance:

Currently changing an immutable collection naively creates a complete copy of the original collection, none of the internal structure is reused, which means each mutating operation is at least O(n).