0.8.0

Added

• h2:respond/5 sends a complete response (status, headers and body) in one call
  and one coalesced socket write (HEADERS plus DATA), instead of the two
  round-trips of send_response/4 followed by send_data/4. It falls back to
  the granular path when the response cannot be coalesced (oversized headers or
  body, CONNECT tunnels). The existing send functions are unchanged.
• backlog server option (default 1024) sizes the listen queue.

Fixed

• Connection collapse under concurrent load. The server dropped responses for
  requests pipelined before the client's SETTINGS-ACK (legal per RFC 9113): a
  handler's send_response/send_data was rejected while the connection was
  still in the settings state, so fast clients (h2load, browsers) lost whole
  connections under load. The server now serves while in the settings state.
• Client stream leak. Response HEADERS without END_STREAM reset a
  half_closed_local stream back to open, so the final DATA reached only
  half_closed_remote and completed streams never closed, eventually exhausting
  SETTINGS_MAX_CONCURRENT_STREAMS.

Changed

• HPACK encoder static-table lookup is an O(1) precomputed map, and the dynamic
  table is a map keyed by insertion sequence for O(1) indexed lookup, insert and
  eviction (was lists:nth/2).
• HPACK Huffman decoding is a table-driven 8-bit state machine (one tuple lookup
  per input byte); cold header decode is about 9x faster.
• DATA frames are sent as iodata without copying the body.