Concurrent Collections Manager and Custom Exception

Dear DotNet Core 2.1 developer, I am looking for a professional with experience in DotNet Core 2.1, 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 methods to manipulate them. In this tasks you will also create an encapsulation for a Custom Exception. Attached is a detailed specification with the requirements. I would like to work on hourly basis, with screenshot monitoring, but keeping a limit on the price of the task. This task should be completed in 3-4 days. Please submit your bids.