defaultMetricNameSanitizer
Default implementation of LabelSanitizer
that sanitizes any “:” occurrences by replacing them with a replacement character. Defaults to replacing the illegal characters with “_”, e.g. “offending:example” becomes “offending_example”.
static let defaultMetricNameSanitizer: StatsdClient.MetricNameSanitizer
See https://github.com/b/statsd_spec
for more info.