@Override
  public boolean isConnected() {
    return connected;
  }
Determines whether this HTTP-based OperationInvoker is successfully connected to the remote
GemFire Manager's HTTP service in order to send commands for execution/processing.

@return a boolean value indicating the connection state of the HTTP-based OperationInvoker.
geode-gfsh/src/main/java/org/apache/geode/management/internal/web/shell/HttpOperationInvoker.java