"Service was not ready: transport error" when making gRPC request.

## Bug Report
Encounter "Service was not ready: transport error" when making gRPC requests on from a client. The client was cloned before each request.

### Version
tonic = "0.12"

### Description
A grpc client was created at startup before serving my backend APIs. There are a bunch of setups but the following highlighted the gRPC client setup:

```
pub struct Router {
pub gprc_client: Arc,
....
}

fn main() {
let router = {
let rt = tokio::runtime::Builder::new_multi_thread()
.enable_all()
.worker_threads(config.thread_config.total_thread_count)
.build()
.unwrap();

rt.block_on(async move {
let client = get_grpc_client("https://rtse-api-service.rtse.svc.cluster.local/").await.unwrap()
let router = Router {
gprc_client: Arc::new(client),
};

router
})
};

let rt = tokio::runtime::Builder::new_multi_thread()
.enable_all()
.worker_threads(5)
.build()
.unwrap();

rt.block_on(run_api(router)).unwrap();
}

async fn get_grpc_client(url: String) -> Option {
let channel = Endpoint::from_shared(url);
match channel {
Ok(endpoint) => Some(
MyServiceClient::new(endpoint.connect_lazy())
.accept_compressed(tonic::codec::CompressionEncoding::Zstd)
.send_compressed(tonic::codec::CompressionEncoding::Zstd),
),
Err(_) => None,
}
}
```
For each request I am cloning the client in order to handle concurrent request:

```
pub async fn handle_request(&self) {
...
let gprc_client = (*self.gprc_client).clone();
let request = Request::new(GetRequest {
param_a: ...,
param_b: ...,
});

let result = gprc_client.handle_grpc_request(request).await;

match result {
Ok(result) => {
...
},
Err(err) => {
let error_code = err.code();
let error_message = err.message();

// Got Error: Unknown error: Service was not ready : transport error
log::error!("Got Error: {error_code} : {error_message}");
}
}
}
```

Could someone help me understand this error better? Thanks!