This is a .NET Standard library for aggregating read-only streams, so that classes like StreamReader can treat multiple input streams as a single contiguous block of bytes.
Usage:
var ms1 = GetStream("hello world");
var ms2 = GetStream("goodbye world");
var s = new Lib.MultiStream(ms1, ms2);
var reader = new StreamReader(s);
var output = reader.ReadToEnd();
Assert.AreEqual("hello worldgoodbye world", output);
The repo includes a .NET Core unit test project and a .NET Framework console app that both demonstrate basic usage.