Support incomplete input

[teubert]

Requirement Text
prog_server shall allow an incomplete data frame is sent to the service

Background Information
models take more than one input and output. sometimes they're received at different rates. The service should be able to handle this and only start a state estimate when we've received a full data frame

Suggested Solution
Keep track of received data. When all required inputs and outputs have been received, trigger state estimation

DoD

• Implement feature
• Add to example
• Add tests
• Add to change notes for next release