Support for connecting and writing span of bytes

[popcron]

the availability of span overloads is great and really useful. there was just a few missing API that i need for my work:

• connecting with a span of bytes (2b0d8c0)

Span<byte> connectionData = stackalloc byte[32];
//write data into connectionData manually
NetManager client = new();
client.Start();
client.Connect("localhost", 1337, connectionData);

• putting a span of bytes into a NetDataWriter (2eb2cbe)

Span<byte> messageData = stackalloc byte[32];
NetDataWriter netWriter = new();
netWriter.Put(messageData);
netPeer.Send(netWriter, DeliveryMethod.ReliableOrdered);

tests were also added to check sanity check both under the NET5_0_OR_GREATER flags