@callback receive_error(
  reason :: term(),
  client_or_server_key ::
    Sippet.Transactions.Client.Key.t() | Sippet.Transactions.Server.Key.t()
) :: any()

Receives an error from the server or client transaction.

The function receive_error/2 is called from the client or server transaction process created when sending or receiving requests.

@callback receive_request(
  incoming_request :: Sippet.Message.request(),
  server_key :: Sippet.Transactions.Server.Key.t() | nil
) :: any()

Receives a new incoming request from a remote host, or ACK.

The server_key indicates the name of the transaction created when the request was received. If it is an ACK, then the server_key is nil.

The function receive_request/2 is called from the server transaction process when the parameter server_key is not nil, and from the transport process (possibly a poolboy worker process), when the server_key is nil.

@callback receive_response(
  incoming_response :: Sippet.Message.response(),
  client_key :: Sippet.Transactions.Client.Key.t() | nil
) :: any()

Receives a response for a sent request.

The client_key indicates the name of the transaction created when the request was sent using Sippet.Transactions.send_request/1.

The function receive_response/2 is called from the client transaction process when the parameter client_key is not nil, and from the transport process (possibly a poolboy worker process), when the client_key is nil.