@Nullable
    @Deprecated
    public String defaultServiceName() {
        return defaultServiceName;
    }
Returns the default value of the {@link RequestLog#serviceName()} property which is used when
no service name was set via {@link RequestLogBuilder#name(String, String)}.
If {@code null}, one of the following values will be used instead:
<ul>
  <li>gRPC - a service name (e.g, {@code com.foo.GrpcService})</li>
  <li>Thrift - a service type (e.g, {@code com.foo.ThriftService$AsyncIface} or
      {@code com.foo.ThriftService$Iface})</li>
  <li>{@link HttpService} and annotated service - an innermost class name</li>
</ul>

@deprecated Use {@link #defaultServiceNaming()} instead.
core/src/main/java/com/linecorp/armeria/server/ServiceConfig.java