riki 

Extremely fast binary serializer with tons of features. Full reference persistence (including circular references), polymorphism, zero-allocations, can handle readonly fields, delegates, 'KnownTypes' list for whitelisting and optimization in network scenarios... checkout the github page for a... More information

This package adds formatters for all the types in the System.Collections.Immutable namespace. For example ImmutableArray, ImmutableSet, ImmutableDictionary, ...