public Builder addExtraAttributes(String key, Collection<String> values) {
            this.extraAttributes.computeIfAbsent(requireNonNull(key), __ -> new ArrayList<>()).addAll(requireNonNull(values));
            return this;
        }
A immutable request log entry

@author bjorncs
container-core/src/main/java/com/yahoo/container/logging/RequestLogEntry.java