Export the definition of Change in tower::discover rather than rewriting it.

[accestfromim]

Export the definition of Change in tower::discover rather than rewriting it.

Motivation

the issue #2049 reported a bug but I couldn't reproduce it. However, while trying to reproduce it, I noticed that the definition of enum Change is duplicated, so I was thinking if should export it instead of rewriting it.

Solution

before:
n tonic/src/transport/channel/service/discover.rs line 14-20

#[derive(Debug, Clone)]
pub enum Change<K, V> {
    /// A new service identified by key `K` was identified.
    Insert(K, V),
    /// The service identified by key `K` disappeared.
    Remove(K),
}

and it is just the same as in tower::discover::Change

after:

pub use tower::discover::Change;

[tottoto]

It is an intentional design not to expose tower crate's type as external API. You should track the history and try to find how they were intended at first, when you have any questions about the implementations.