What this measures

Two peer connections inside this one page, so there is no network between them. That isolates what the engine costs — chunking, AES-256-GCM, backpressure and the streaming sink — from what the network costs. Stage 1 is the ceiling for this machine; the later stages show how much of that ceiling the real pipeline keeps.

Results

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Reference points

• 1 MB stop-and-wait at 50 ms RTT≈ 160 Mb/s ceiling
• 1 MB stop-and-wait at 100 ms RTT≈ 80 Mb/s ceiling
• Typical default-configuration browser data channel≈ 145 Mb/s
• Peak JS heap while receiving, buffering design≥ file size
• Peak JS heap while receiving, streaming designflat, ~10 MB