Definition of the SNTP Context data structure

If calling the NAgetSntpCtx() function it returns a pointer to a SNTP context, which should deliver a more accurate time. But unfortunately NAgetSntpCtx() returns a void pointer and I can not find any hint or documentation which describes the struct of the SNTP context.

Does anyone have an idea where this SNTP context is described or defined?

Thanks a lot!
Ralph