public StartOperationAuditEventBuilder withHostname(String hostname) {
      this.hostname = hostname;
      return this;
    }
Sets the identifier of the operation through which the operation progress can be tracked.

@param requestId the identifier of the operation through which the operation progress can be tracked.
@return this builder
ambari-server/src/main/java/org/apache/ambari/server/audit/event/request/StartOperationRequestAuditEvent.java