InternalGrpcExceptionHandler getExceptionHandler(ServerMethodDefinition<?, ?> methodDef) {
        return grpcExceptionHandlers.getOrDefault(methodDef, defaultExceptionHandler);
    }
A registry of the implementation methods bound to a {@link GrpcService}. Used for method dispatch and
documentation generation.
grpc/src/main/java/com/linecorp/armeria/server/grpc/HandlerRegistry.java