code: func RecordMemoryUsage(memMB float64) (int, error) {
  	return errNo(C.newrelic_record_memory_usage(C.double(memMB)))
  }
docs: /*
   * Record the current amount of memory being used.
   *
   * @param memory_megabytes  amount of memory currently being used
   * @return  0 on success, else negative warning code or error code
   */