...The plugin can also retrieve credentials from a shared credentials file, or from the standard AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_SESSION_TOKEN environment variables. A template in the form of $(variable) can be set in log_group_name or log_stream_name. variable can be a map key name in the log message. To access sub-values in the map use the form $(variable['subkey']). Also, it can be replaced with special values to insert the tag, ECS metadata, or a random string in the name. It can achieve higher throughput and will consume less CPU and memory.