def to_s(filter=nil)
log_msg = "#{super} <#{token}> #{type}"
log_msg += " from #{id_to_s(from)}" if filter.nil? || filter.include?(:from)
log_msg += " to #{id_to_s(target)}" if target && (filter.nil? || filter.include?(:target))
log_msg += ", reply_to #{id_to_s(reply_to)}" if reply_to && (filter.nil? || filter.include?(:reply_to))
log_msg += ", tags #{tags.inspect}" if tags && !tags.empty? && (filter.nil? || filter.include?(:tags))
log_msg += ", payload #{payload.inspect}" if filter.nil? || filter.include?(:payload)
log_msg
end