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"""
CloudStack image server — HTTP server backed by NBD over Unix socket or a local file.

Transfer configs are registered/unregistered by the cloudstack-agent via a
Unix domain control socket (default: /var/run/cloudstack/image-server.sock)
and stored in-memory for the lifetime of the server process.

Supports two backends (configured per-transfer at registration time):
- nbd: proxy to an NBD server via Unix socket; supports range reads/writes
  (GET/PUT/PATCH), extents, zero, flush.
- file: read/write a local qcow2/raw file; full PUT only, GET with optional
  ranges, flush.

Run as a systemd service by the CreateImageTransfer CloudStack Agent Command
"""