Set a human readable description of the current job.
Currently, setting a job description (set to local properties) with multiple
threads does not properly work. Internally threads on PVM and JVM are not synced,
and JVM thread can be reused for multiple threads on PVM, which fails to isolate
local properties for each thread on PVM.
To avoid this, enable the pinned thread mode by setting PYSPARK_PIN_THREAD
environment variable to true and uses pyspark.InheritableThread.