folder-transfer v0.11.3

Changed

• Adaptive compression — try, and back off when it doesn't help. For large files the per‑block
  compressor now measures each 1 MB block: if it doesn't shrink (≥ 5 %) the block is sent raw, and
  after a few poor blocks the server stops compressing for a while before probing again. So no CPU
  is wasted compressing data that doesn't compress (e.g. an unknown but already‑compressed format),
  and incompressible data is never expanded on the wire. Known already‑compressed extensions still
  skip compression up front.