*  **OkHttp now rejects request headers that contain invalid characters.** This
    includes potential security problems (newline characters) as well as simple
    non-ASCII characters (including international characters and emoji).

 *  **Call canceling is more reliable.**  We had a bug where a socket being
     connected wasn't being closed when the application used `Call.cancel()`.

Но внутреннее устройство **конкурентности** и **параллелизма** довольно разное.

Чтобы это понять, представьте такую картину:

### Конкурентные бургеры

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