public <T extends Throwable> GrpcExceptionHandlerFunctionBuilder on(
            Class<T> exceptionType, BiFunction<T, Metadata, Status> exceptionHandler) {
        requireNonNull(exceptionType, "exceptionType");
        requireNonNull(exceptionHandler, "exceptionHandler");
        //noinspection unchecked
        return on(exceptionType, (ctx, status, cause, metadata) -> exceptionHandler.apply((T) cause, metadata));
    }
Adds the specified exception mapping that maps a {@link Throwable} to a gRPC {@link Status}.
The mapping is used to handle a {@link Throwable} when it is raised.
grpc/src/main/java/com/linecorp/armeria/common/grpc/GrpcExceptionHandlerFunctionBuilder.java