PJSIP: Check for channel variable?

Is there a proper way to test for the existence of a channel variable with pjsip without causing warning spam in the CLI and logs? For example:

WARNING[16283][C-0000000c] func_pjsip_endpoint.c: Unknown property ‘chan_var[my_channel_variable]’ for PJSIP endpoint

Using something like ${EXISTS(${PJSIP_ENDPOINT(${my_endpoint},chan_var[my_channel_variable])} or ${ISNULL()} isn’t enough to keep the warnings silent.

In chan_sip I was able to use ${EXISTS(${SIPPEER(${my_sip_peer},chanvar[my_channel_variable])} to check for a channel variable before trying to read it.

Thank you for your help.