Changes

** [https://telemetry.mozilla.org/new-pipeline/dist.html#!cumulative=0&end_date=2017-01-30&keys=__none__!__none__!__none__&max_channel_version=nightly%252F54&measure=URLCLASSIFIER_VLPS_FILELOAD_TIME&min_channel_version=null&product=Firefox&sanitize=1&sort_keys=submissions&start_date=2017-01-23&table=0&trim=1&use_submission_date=0 URLCLASSIFIER_VLPS_FILELOAD_TIME]: time spent loading a variable-length PrefixSet from disk

* Server-related

** [https://telemetry.mozilla.org/new-pipeline/dist.html#!cumulative=0&end_date=2017-04-18&keys=google4!google!__none__!__none__&max_channel_version=nightly%252F55&measure=URLCLASSIFIER_COMPLETE_SERVER_RESPONSE_TIME&min_channel_version=null&processType=*&product=Firefox&sanitize=1&sort_keys=submissions&start_date=2017-03-30&table=0&trim=1&use_submission_date=0 URLCLASSIFIER_COMPLETE_SERVER_RESPONSE_TIME]: response time from the completion server

** [https://telemetry.mozilla.org/new-pipeline/dist.html#!cumulative=0&end_date=2017-01-30&keys=google!__none__!__none__!__none__&max_channel_version=nightly%252F54&measure=URLCLASSIFIER_COMPLETE_TIMEOUT2&min_channel_version=null&product=Firefox&sanitize=1&sort_keys=submissions&start_date=2017-01-23&table=1&trim=1&use_submission_date=0 URLCLASSIFIER_COMPLETE_TIMEOUT2]: whether or not a client timed out while contacting the gethash server

** [https://telemetry.mozilla.org/new-pipeline/dist.html#!cumulative=0&end_date=2017-01-30&keys=__none__!__none__!__none__!__none__&max_channel_version=nightly%252F54&measure=URLCLASSIFIER_COMPLETION_ERROR&min_channel_version=null&product=Firefox&sanitize=1&sort_keys=submissions&start_date=2017-01-23&table=1&trim=1&use_submission_date=0 URLCLASSIFIER_COMPLETION_ERROR]: whether a V4 completion result couldn't be parsed or contained an unknown threat type