@Override
  public String toString() {
    return "(username=" + username + ", keyId=" + keyId + ", issueDate=" + issueDate
      + ", expirationDate=" + expirationDate + ", sequenceNumber=" + sequenceNumber + ")";
  }
Represents the identity information stored in an HBase authentication token.
hbase-client/src/main/java/org/apache/hadoop/hbase/security/token/AuthenticationTokenIdentifier.java