@JsonProperty(JSON_RETENTION_POLICY)
  public DatasetBuilder setRetentionPolicy(String retentionPolicy) {
    this.retentionPolicy = retentionPolicy;
    return this;
  }
Set the retention policy
@param retentionPolicy the retention policy, default is counter based.
@return the retention policy.
ambry-api/src/main/java/com/github/ambry/account/DatasetBuilder.java