jsmad | Javascript MPEG-1 Audio Layer III | Audio Utils library

I am trying to set up an mp3 stream receiver in browser using emscripten and libmad.
I managed to decode mp3 file with low-level api loading it completely to the memory. My next step was to load it in chunks.
In given example I emulate fragmented packages with allocated buffers of random size (from 20 to 40 kbyte) and copy file part by part to those buffers.

My algorithm of decoding correlate with an answer in this question but it is a bit different. The main object is Decoder, it receives fragments by addFragment method. Decoder has a pull of pending fragments and a glue buffer. When user adds first fragment its tail is copied in the first half of the glue buffer. When the second fragment is added it's beginning being copied to the second half of the glue. When decoder reaches the end of active buffer end it switches to glue, and vice versa when glue finishes. I make sure all those buffers parts are consistent and mad_stream points to the same logical byte it was pointing before switching.

Significant fragments from decoder.cpp