Make the resamplers take into account out-of-order samples #47

What's needed?

The resampling actor might receive samples from a stream out of order (i.e. it might receive a sample with a lower timestamp after a sample with a higher timestamp). It should be able to deal with it.

Proposed solution

Sort samples in the internal ring buffer by timestamp before evicting any existing samples instead of blindly evicting the first sample that was added.

Use cases

We decided not to guarantee the ordering of samples in a stream the resampler can consume to make the system more real-time, so a source won't have to care about re-sorting samples, it can just send them as soon as they arrive. The resampler already have to deal with faulty sources (not incoming data for example -> intra/extrapolation).

Alternatives and workarounds

Guarantee that sources provide in-order samples.

Additional context

Note that this means the resampling actor doesn't take timeseries as input, as a timeseries is by definition sorted by timestamp.