Map<String, Object> asMap() {
            Map<String, Object> builder = new HashMap<>();
            builder.put(MetricDefinitions.PROTOCOL_DIMENSION, protocol);
            builder.put(MetricDefinitions.METHOD_DIMENSION, method);
            builder.put(MetricDefinitions.REQUEST_TYPE_DIMENSION, requestType);
            builder.put(MetricDefinitions.STATUS_CODE_DIMENSION, (long) statusCode);
            return Map.copyOf(builder);
        }
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