fix #2366: v5 Mixer crashes when adding 8+ inputs to it while playing
fix #2366: v5 Mixer crashes when adding 8+ inputs to it while playing

(cherry picked from commit ba83d16933358548ae9a87949c114c49b4548404)

adamnemecek/AudioKit,audiokit/AudioKit,adamnemecek/AudioKit,audiokit/AudioKit,audiokit/AudioKit,audiokit/AudioKit,adamnemecek/AudioKit,adamnemecek/AudioKit