zero or more objects which can be coerced to character
(and which are pasted together with no separator) or (for
message only) a single condition object.
domain
see gettext. If NA, messages will
not be translated, see also the note in stop.
appendLF
logical: should messages given as a character string
have a newline appended?
.loggit
Should the condition message be added to the log?
If NA the log level set by set_log_level() is used to determine if the condition should be logged.
echo
Should the log entry (json) be echoed to stdout as well?