Requiem.init

You're seeing just the callback init, go back to Requiem module for more information.
Link to this callback

init(conn, client)

Specs

init(
  conn :: Requiem.ConnectionState.t(),
  client :: Requiem.ClientIndication.t()
) ::
  {:ok, Requiem.ConnectionState.t(), any()}
  | {:ok, Requiem.ConnectionState.t(), any(), timeout() | :hibernate}
  | {:stop, non_neg_integer(), atom()}