"Current" recall is not actually current but cumulative so far #108
Description
We now report the current latency and recall during the run phase - e.g.
Performing Run phase 6990/10000 ━━━━━━━━━━━━━━━━━━━━━━━━━━━╸━━━━━━━━━━━━ 70% elapsed: 0:01:19 remaining: 00:34 Current latency: p5=41ms, p95=52ms | Current recall: p50=0.99, p5=0.97
The current latency figures come from locust itself, which calcualates this from the last 10s worth of samples - so it is indeed a "current" metric.
However the recall figures are recorded by VSB itself from a single HdrHistogram instance, and hence they are the cumulative recall values so far.
This is misleading, as they won't readily adopt to changes to the performance of recall during the experiment.
To address this we need to do something similar to _cache_response_times - retain N copies of the histogram from the last N seconds and use the difference between T=now and T-10 to display them.