New Metric Request: Add Net DNS Resolver Stats

[megamattzilla]

Some customers utilize TMOS net DNS resolvers to deliver critical services such as LTM with an explicit forward proxy configuration.

TMOS provides native statistics for these net DNS resolvers at /mgmt/tm/net/dns-resolver/stats

Some statistics for dns net resolvers that are important for my customers are:

{
"clientHits":{"value":63304},
"clientHitsPercent":{"value":66},
"clientHitsResponseTime":{"value":14},
"clientMisses":{"value":32345},
"clientMissesPercent":{"value":34},
"clientMissesResponseTime":{"value":116208},
"queries":{"value":80366},
"responses":{"value":80366},
"serveExpiredAnswers":{"value":0},
"serverErrFormerr":{"value":0},
"serverErrMemory":{"value":0},
"serverErrOther":{"value":970},
"serverErrPortV4":{"value":0},
"serverErrPortV6":{"value":0},
"serverErrRouteV4":{"value":0},
"serverErrRouteV6":{"value":424584},
"serverErrServfail":{"value":7}
}

It would be great to have these added to OTEL collector.

Note: this is not quite the same thing as TMOS GTM Cache; however, the stats output appears to be the same.