C# adapter

[eulerfx]

Create a CSharp.fs with namespace Kafunk.CSharp with adapters for idiomatic C#. Some thoughts:

• Convert Async to Task.
• Convert the functional ADP style, to a OOP style:
  • KafkaConnection class wrapping KafkaConn, with methods for each API operation.
  • KafkaConsumer class wrapping Consumer, with methods to start consumption, accepting a callaback
  • KafkaProducer class wrapping Producer, with a method to produce a message.