A connection to a Discord voice server (voice gateway v8): one per guild.

It takes the session details the main gateway hands out (session_id from VOICE_STATE_UPDATE, token and endpoint from VOICE_SERVER_UPDATE), so it depends on nothing global and several bots can run side by side.

Media is end-to-end encrypted with DAVE whenever the call uses it, then transport encrypted over UDP. Subscribers receive:

• {:lingo_voice, guild_id, :ready} once connected; with DAVE on, audio is only sent once the group keys are in place, so playback asked for before then waits and starts from its first packet (see info/1)
• {:lingo_voice, guild_id, {:audio, user_id, packet}} for each Opus packet received, where packet has :opus, :sequence and :timestamp
• {:lingo_voice, guild_id, {:speaking, user_id, flags}}
• {:lingo_voice, guild_id, :playback_finished}
• {:lingo_voice, guild_id, {:playback_failed, reason}} when the audio source fails, for example ffmpeg can't read the input
• {:lingo_voice, guild_id, {:disconnected, reason}}