internal/timeseries: avoid storing numbers as durations
internal/timeseries: avoid storing numbers as durations

... even if it does avoid a cast. advance isn't a duration and shouldn't be typed that way.

Change-Id: I6328188e74010d6c57adf5b26beede57b3bc7e33
GitHub-Last-Rev: 281097649e15c343e72cc51ecbeda31e81f9b6b3
GitHub-Pull-Request: golang/net#29
Reviewed-on: https://go-review.googlesource.com/c/net/+/161297
Run-TryBot: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

golang/net