anchor.diff:  By adding `io.github.lognet:grpc-client-spring-boot-starter` dependency to your *java grpc client* application you can easily configure per-channel or per-call credentials :
   
   * Per-channel :
  -
  ++
   [source,java]
   ----
   class MyClient{
  
positive.code: You can find  link:grpc-spring-boot-starter-demo/src/main/resources/META-INF/validation/constraints-person.xml[demo configuration] and corresponding tests
  link:grpc-spring-boot-starter-demo/src/test/java/org/lognet/springboot/grpc/ValidationTest.java[here]
  
  Note, that both `request` and *response* messages are being validated.
  
  If your gRPC method uses the same request and response message type, you can use `org.lognet.springboot.grpc.validation.group.RequestMessage` and
  `org.lognet.springboot.grpc.validation.group.ResponseMessage` validation groups to apply different validation logic  :
  
negative.code: <3> Provide token generator function (Please refer to link:grpc-spring-boot-starter-demo/src/test/java/org/lognet/springboot/grpc/auth/JwtAuthBaseTest.java[for example].)
  
  * Per-call :
  +
  [source,java]
  ----
  class MyClient{
  