Disambiguate varadic list push operations (fix overloaded and competi…

…ng optional parameters)

AppVeyor: Install .NET 5.0 SDK (StackExchange#1613)

* AppVeyor: Install .NET 5.0 SDK

* Move NerdBank to src\ only

prefix the new exception keys correctly; fix possible NRE cause in Cu…

…rsorEnumerable

fix a System.Buffers break via System.IO.Pipelines; 4.7.2 adds a netf…

…x TFM, which in turn adds System.Buffers breaks

- we now only take a dependency on 4.7.1, which means we don't *force* the issue on people
- Pipelines.Sockets.Unofficial has been updated to identify the problem clearly

avoid the array (multi-bulk) allocation in sentinel processors (Stack…

…Exchange#1491)

* avoid the array (multi-bulk) allocation in sentinel processors

* release notes

fix build

release notes

2.1.0 Release! (StackExchange#1394)

This bumps versioning for the 2.1.0 release, ready to GA!

add tracking for "now" and "next" messages when recording message tim…

…eouts

release notes for 2.0.593