[Java][Flight] How can a FlightClient connect to multiple servers?

### Describe the usage question you have. Please include as many useful details as possible.

Our backend service is a cluster that allows clients to connect to any service. How does a FlightClient connect to multiple servers and maintain the authentication status. Our goal is load balancing. The server uses FlightService and grpc Server, but the authentication is in FlightService. I don't know how to maintain the authentication status of multiple servers in one FlightClient.

### Component(s)

Java

El issue menciona FlightClient, FlightService y el gRPC Server; empieza rastreando cómo el cliente Java gestiona las conexiones y cómo se establece la autenticación en FlightService. Determina si se pueden usar varios servidores conservando la autenticación para el balanceo de carga; se considera terminado cuando haya una respuesta concreta y documentada o un follow-up claramente delimitado.

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