static MetricsPacket.Builder adjustTimestamp(MetricsPacket.Builder builder, Instant startTime) {
        Duration age = Duration.between(startTime, builder.getTimestamp());
        if (age.abs().minusMinutes(1).isNegative())
            builder.timestamp(startTime);
        return builder;
    }
If the metrics packet is less than one minute newer or older than the given startTime,
set its timestamp to the given startTime. This is done to ensure that metrics retrieved
from different sources for this invocation get the same timestamp, and a timestamp as close
as possible to the invocation from the external metrics retrieving client. The assumption
is that the client requests metrics periodically every minute.
<p>
However, if the timestamp of the packet is too far off in time, we don't adjust it because
we would otherwise be masking a real problem with retrieving the metrics.
metrics-proxy/src/main/java/ai/vespa/metricsproxy/core/MetricsManager.java