Race condition when reusing OauthClient across goroutines

[francescobianco]

Description
Using a shared OauthClient in concurrent workers causes inconsistent token responses.

Code snippet

oauthClient := client.NewOauthClient(user, apiKey, true)

wg := sync.WaitGroup{}
for i := 0; i < 10; i++ {
    wg.Add(1)
    go func() {
        defer wg.Done()
        _, _ = oauthClient.CreateToken(context.Background(), scopes, 3600)
    }()
}
wg.Wait()

Observed behavior
Occasional malformed responses or errors.