question: protected boolean isSideChannelActive ( ) { return System . getenv ( SIDECHANNEL_AUTH_ENV_NAME ) != null ; }
target:  Returns whether it appears that side channel auth should be used when creating the SchedulerDriver. Side channel auth may take the form of Bouncer-based framework authentication or potentially other methods in the future (eg Kerberos). Broken out into a separate function to allow easy customization in tests.