Allow authoritative match join attempts to carry metadata. Improve sample lua modules.

### Added

- More flexible query-based filter when listing realtime multiplayer matches.

- Runtime function to batch get groups by group ID.

- Allow authoritative match join attempts to carry metadata from the client.

### Changed

- Improved cancellation of ongoing work when clients disconnect.

end

nk.register_rpc(send_stream_data, "clientrpc.send_stream_data")

local function create_authoritative_match(_context, _payload)

  local match_id = nk.match_create("match", { debug = true })

local function create_authoritative_match(_context, payload)

  local decoded = nk.json_decode(payload)

  local params = {

    debug = (decoded and decoded.debug) or true,

    label = (decoded and decoded.label)

  }

  local match_id = nk.match_create("match", params)

  return nk.json_encode({ match_id = match_id })

end

nk.register_rpc(create_authoritative_match, "clientrpc.create_authoritative_match")

  node: "name of the Nakama node the user is connected to"

}

Metadata is an optional set of arbitrary key-value pairs received from the client. These may contain information

the client wishes to supply to the match handler in order to process the join attempt, for example: authentication or

match passwords, client version information, preferences etc. Format:

{

  key: "value"

}

Expected return these values (all required) in order:

1. An (optionally) updated state. May be any non-nil Lua term, or nil to end the match.

2. Boolean true if the join attempt should be allowed, false otherwise.

--]]

local function match_join_attempt(context, dispatcher, tick, state, presence)

local function match_join_attempt(context, dispatcher, tick, state, presence, metadata)

  if state.debug then

    print("match join attempt:\n" .. du.print_r(presence))

    print("match join attempt metadata:\n" .. du.print_r(metadata))

  end

  return state, true

end

  end

end

function M.match_terminate(context, dispatcher, tick, state, grace_seconds)

  return nil

end

return M