Provide a way to set decoration order

The order of decoration depends on the order of insertion. https://armeria.dev/docs/client-decorator#the-order-of-decoration A decorator inserted later has a higher priority for the client-side. In contrast, a routing decorator inserted earlier has a higher priority for the server-side.

If a decorator has an explicit order, it would be useful for designing a complex decorating chain. For example:

Server.builder()
      .decorator(LoggingService.newDecorator(), 1)
      .decorator(EncodingService.newDecorator(), 2)
      ...
      .build()

[heowc]

Can I work on it?

[ikhoon]

Decorators are always executed in the reverse order of the insertion. Some implementations did not flow the rule such as the routing decorator. It also gives confusion to users. Had chat this feature, which sets a decorator with an order, with other maintainers and we reached that this API can cause another confusion. Please file an issue or leave a comment on this thread if an explicit order of decoration is necessary.