@Override
    public DefaultServiceConfigSetters setHeaders(
            Iterable<? extends Entry<? extends CharSequence, ?>> defaultHeaders) {
        requireNonNull(defaultHeaders, "defaultHeaders");
        ensureNoPseudoHeader(defaultHeaders);
        this.defaultHeaders.setObject(defaultHeaders);
        return this;
    }
A default implementation of {@link ServiceConfigSetters} that stores service related settings
and provides a method {@link DefaultServiceConfigSetters#toServiceConfigBuilder(Route, String, HttpService)}
to build {@link ServiceConfigBuilder}.
core/src/main/java/com/linecorp/armeria/server/DefaultServiceConfigSetters.java