Egress via AF SDK

Please add AF SDK Egress as an additional optional egress component. This would be very helpful for customers who are using the adapters, but keeping the PI Server on-premise.

The adapters are relatively light-weight services; however, the “cost” of egressing data via OMF to an on-premise PI Server is that there is additional complexity introduced for receiving data:

1) Each WebAPI seems only able to receive data from five adapters, and each WebAPI requires 4 core and 8GB RAM. This has a significant cost attached, both OPEX and CAPEX.

2) Additional complexity to set up a load balancer in front of all the WebAPI machines

3) Data flow is Adapter buffer --> OMF egress to WebAPI --> pibufss (using AF SDK) --> PI Data Archive. This could be simplified if the adapter buffer can be cleared directly to pibufss using AF SDK without requiring the use of OMF in the middle. This may improve data throughput by utilising PINET to transfer the data instead of HTTPS which suffers badly over high latency connections.

The implementation difficulty currently is that pibufss and AF SDK are both not cross-platform. With AF SDK migrating to the latest .NET Core, that may change. Since the adapter has its buffer mechanism, the main utility of pibufss would be to manage the data fanning to multiple members of the PI collective. It may be possible to manage the fanning in the adapter's own buffer mechanism and pibufss would not be used at all.