fix: Don't increment counter in Awake (MirrorNetworking#971)

Doing it in Awake and also before assigning to clients skips connection ID 1.

fix: do not accumulate changes if there are no observers fixes Mirror…

…Networking#963 (MirrorNetworking#964)

* fix: do not accumulate changes if there are no observers MirrorNetworking#963

* Update NetworkIdentity.cs

fix: maintain Unity's copyright notice (MirrorNetworking#961)

fix: Telepathy forgot to set socket options for accepted clients on t…

…he server

perf: Recycle argument writer to avoid allocations (MirrorNetworking#945

)

* Recycle argument writer

* Get a pooled networkwriter for argumens

* Use pool,  not static variable

* Use explicit type

* Remove blank space

* Recycle writer in the weaver where it is allocated

perf: remove allocations during syncvar sync (MirrorNetworking#946)

fix: properly stop client and server in OnApplicationQuit so that cli…

…ents still get a chance to send then 'quit' packet instead of just timing out. Also fixes a bug where OnStopServer/OnStopClient were not called when stopping the Editor. (MirrorNetworking#936)

perf: use 0 for null strings (MirrorNetworking#926)

* Use 0 for null strings

* Fix test

* No need for special case for ""

* No need for special case for ""

* Update Assets/Mirror/Runtime/NetworkReader.cs

Co-Authored-By: Paul Pacheco <[email protected]>

perf: Use 0 for null byte arrays (MirrorNetworking#925)

* Use 0 for null byte arrays

* Update Assets/Mirror/Runtime/NetworkWriter.cs

Co-Authored-By: Paul Pacheco <[email protected]>

* Update comments

* Update Assets/Mirror/Runtime/NetworkReader.cs

Co-Authored-By: Paul Pacheco <[email protected]>

* Update Assets/Mirror/Runtime/NetworkReader.cs

Co-Authored-By: Paul Pacheco <[email protected]>

fix: TelepathyTransport.ToString UWP exception