L5D-Sample header is checked against static value

[klingerf]

The L5D-Sample header should allow you to specify a sample rate, such that a corresponding percentage of requests with that header are sampled. For instance, if I set L5D-Sample: 0.2 on 100 requests, I'd expect roughly 20 requests to be sampled.

Instead, it looks like the value of that header is being checked against a float value that remains constant for the lifetime of the linkerd process. For instance, if the threshold that's determined when linkerd starts is 0.35, 0% of requests with the L5D-Sample: 0.3 header will be sampled, and 100% of requests with the L5D-Sample: 0.4 header will be sampled. When the process restarts it picks up a new threshold at random.

[klingerf]

Ok, it looks like the root cause of this issue is actually #82.