For future reference:
1. First, download the proper Lightstreamer client demo:
2. Download the following nuget packages :
Some things to note:
Make sure the version for Lightstreamer client is 4.0.0 (this is the only version that the Forex Servers are currently working with).
In this demo I am using the latest logging service (NLog 4.7.4) -- this is the one that Lightstreamer is currently using in their version 5+ demos. You will need to make sure your Wrapper class is also the latest version.
This works with .NET Core 3.0 and previous .net framework versions.
3. Setup your client and subscription.
This is the C# code to setup and connect to the Prices streaming server: