fn build_families(
published: &BTreeMap<(String, Vec<(String, String)>), (f64, MetricKind, String)>,
) -> Vec<MetricFamily>Expand description
Groups published by metric name into one MetricFamily per name, since Prometheus requires
a single type and help string per family. Within a group, the entry with the
lexicographically smallest label vector wins the family’s type and help string;
BTreeMap’s (name, labels) key ordering already sorts each group that way, so the
first entry seen for a given name is that winner.
MetricFamily.type_ and Metric.{gauge,counter} are protobuf wrapper types
(EnumOrUnknown/MessageField).