Stream API is unsound

[micahrj]

The callback is passed a 'static reference to the audio buffer (here and here; also see Output and Duplex), which allows the reference to outlive the duration of the callback. The lifetime of the buffer should be appropriately constrained to the duration of the callback.

[forslund]

I think I ran into this when trying to send the buffer over a channel: https://github.com/forslund/rust-recorder/blob/ea1256907b9b27987385288f4ced362111b4c170/src/main.rs