Add outgoing audio packet interval option

README.md

@@ -140,6 +140,20 @@ If you modify the config file while Barnard is running, your changes may be over
 You can set username and defaultserver in your config file, and they will be used if none is specified when launching barnard.
 (Note that the default username (an empty string) and the default server name (localhost:64738) have been the defaults for barnard up to this  point, and have been left that way for compatibility.)
 
+## Audio Packet Duration
+
+Barnard sends 10 ms audio packets by default. On a slow or unstable connection,
+using larger packets can reduce packet overhead and make short dropouts less
+noticeable, at the cost of additional voice latency. Start Barnard with one of
+the supported durations:
+
+```sh
+barnard --audio-interval 20
+```
+
+Supported values are `10`, `20`, `40`, and `60` milliseconds. Try `20` ms
+first; use `40` ms only if the connection remains unreliable.
+
 ## Audio Devices
 
 You can set the default input and output devices in the config file as well.