Support ArraySegment bodies in BasicPublish

[Astomat]

Hello,
It will be very helpful to have the ability to receive ArraySegment body in BasicPublish method.
I have many cases in which memory needs to copied in order to build the proper body byte array instead of just defining a segment in byte array buffers.
Another posibility is to accecpt offset and length in addition to body byte array.

Thanks,
Astomat

[michaelklishin]

@kjnilsson sounds like a new override we can safely introduce? thoughts?

[kjnilsson]

Sounds like a good idea. There may be a few changes to make for this but definitely worth investigating.

[stebet]

It would be smart to also allow using Memory. To utilize memory pooling/recycling efficiently another one using IMemoryOwner (supported in the System.Memory NuGet packages for .NET Framework) making it possible to often avoid memory copies (almost entirely when pipelines are introduced) when publishing.

[lukebakken]

I think it's safe to assume that #706 and other improvements in version 7.0.0 will address this issue.