created(broker) {
			logger = broker.getLogger("TX-COMPRESS");
			/* istanbul ignore next */
			logger.info(
				`The transmission is COMPRESSED by '${opts.method}'. Threshold: ${
					threshold != null ? opts.threshold : "none"
				}`
			);
		}
This is a transmission compression middleware. It supports
the `deflate`, `deflateRaw` & `gzip` compression methods.

@param {String?} opts.method
@param {String|Number} opts.threshold