makeNetworkInterface does not accept a ServiceContext*. When called, it will acquire a pointer to the global service context should a global context exist. If makeNetworkInterface cannot acquire a global context, such as if it is invoked before the global service context is installed, it will construct a NetworkInterfaceTL with a NULL ServiceContext. When this happens, NetworkInterfaceTL will construct its own owned TransportLayer.

This means that every ThreadPoolTaskExecutor made in a decoration's default constructor or in a ServiceContext::ConstructorActionRegisterer will possess its own TransportLayer.