private boolean shouldLogMetricsFor(Request request) {
        String agent = request.getHeaders().get(HttpHeader.USER_AGENT);
        if (agent == null) return true;
        return ! ignoredUserAgents.contains(agent);
    }
A {@link RequestLog} implementation that collects statistics like HTTP response types aggregated by category.
Implemented as a {@link RequestLog} instead of {@link org.eclipse.jetty.server.handler.EventsHandler} to ensure
that 400 responses from e.g. invalid request headers are also included.

@author ollivir
@author bjorncs
container-core/src/main/java/com/yahoo/jdisc/http/server/jetty/MetricAggregatingRequestLog.java