Concurrent Collections Manager and Custom Exception -- 2

Dear DotNet Core 2.2 developer, I am looking for a professional with experience in DotNet Core 2.2, Autofac Dependency Injection, and NUnit unit testing (with Moq when appropriate), to develop the following: There are 4 concurrent collection types which I want to encapsulate into a single class library, exposing standardised interface methods to manipulate them. In this task you will also create an encapsulation for a Custom Exception. This task should be completed in 3-4 days. The task will only be accepted (to release payment) providing high quality code. Please submit your bids.