The log_mask key enables component-level logging for any of the following components. When more than one component is specified, separate the component names with colons (:).
UVPROC enables logging of calls to libuv read/write functions.
SSLPROC enables logging of SSL functions.
QUEUE enables logging of internal queue usage.
JOB enables job-related logging.
Change this setting using one of the following methods:
API custom configuration channels (see Using API Custom Configuration Channels).
Manually on individual endpoints using a text editor (see Modifying the Configuration File for a Single Endpoint).