# Functions
Default Configurer does nothing but ensure default config was set.
Disable returns a configurer to disable reqlog.
DoubleLog returns a configurer to enable or disable double log.
Logger Configurer sets logger.
NewDefaultOption creates default option.
RequestID returns a configurer to enable or disable showing request id.
RequestIDKey returns a configurer to set header key of request id.
SourceAddr returns a configurer to enable or disable showing source addr.
# Constants
ExternalConfigName is the external config name of request logger.