Add a way to pin variables or steps in streaming mode to allow access to variables that are not sent at every step
Created by: fbudin69500
It happens frequently that some data is saved or sent only at certain steps. For example, the geometry of the mesh is often only written on the first step. When using a streaming engine like SST, one reader that connects later than when the data was written will miss this important piece of data that maybe is sent only once. It would be convenient to have a way to pin some steps that are complete (contain all the variables), or individual variables that need to be read on the first step of the processing when a new reader connects.