record_wav example always writes very first recorded audio

[aztecrex]

Running the example multiple times always produces the first recording I made.

Macbook M1, MacOS Montery, rustc v1.65

To reproduce:

# run the example (and say something)
cargo run --example record_wav
# listen to the result
open recorded.wav
# delete the recording
rm recorded.wav
# run the example again (and say something else)
cargo run --example record_wav
# listen to the result
open recorded.wav

No matter how many times I remove the recording and run the example, I get the very first recorded audio.