Option to collect latencies for individual requests

Currently, the only option in PerformanceEvaluation is to print latency percentile summary at the end, and it is also not suitable if we are testing for a long duration (as all the timings are collected in memory). There should be an option to dump the latencies with a timestamp as CSV to a file so that this allows a detailed analysis on the generated data, such as:

• Percentile calculation at the desired precision on the latencies
• Latencies over time
• Histograms