@JsonProperty(JSON_PROPERTY_USED)
  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
  public void setUsed(Integer used) {
    this.used = used;
  }
used size of memory in bytes
minimum: 0
maximum: 4294967295
@return used
plc4j/drivers/ctrlx/src/main/java/org/apache/plc4x/java/ctrlx/readwrite/rest/datalayer/model/RetainStats.java