CHANGES:

• Improve connection shutdown (#22).
  Add shutdown and up methods to the transport API.
  Call shutdown to start a clean shutdown of the connection.
  Use up to detect that a connection is shutting down (to avoid logging pointless errors).
  Add close and socket methods to unix_transport.

• Log exceptions handling messages instead of aborting the connection (#21).
  Most errors are not fatal, and closing the connection means the application can't even e.g. prompt the user to save their work.

• Add Client.dump and Server.dump (#20). Useful for finding object reference leaks.

• Add Proxy.pp_transport (#19). Useful for logging when you have multiple connections.

• Also call on_delete handlers when the connection ends (#18).
  Allows them to be used for cleaning up resources.

• Add set_paused to pause processing of incoming messages (#17).

• Add Proxy.can_send (#16).
  This is useful to check whether a proxy has been destroyed.

• Raise Invalid_argument on Proxy.id if the proxy is destroyed.

• Add wp_primary_selection_unstable_v1.
  This appears to be identical to gtk-primary-selection except for the name and that it's marked as unstable.
  But sway has dropped support for the old name (see swaywm/sway#5788).

• Update to latest Fmt API.

• Fix deprecation warning with cstruct 6.0.1.