Behaviour for LSN position persistence.

By default, TdsCdc.Persistence.File writes LSN positions to disk so they survive application restarts. You can implement this behaviour to store positions in a database, Redis, or any other backend.

Example: custom persistence module

defmodule MyApp.DbPersistence do
  @behaviour TdsCdc.Persistence

  @impl true
  def save_positions(_name, positions) do
    # Write positions to your database
    :ok
  end

  @impl true
  def load_positions(_name) do
    # Read positions from your database
    {:ok, %{}}  # or {:error, reason}
  end
end

Then pass it to the client:

TdsCdc.start_link(
  conn: [...],
  capture_instances: ["dbo_users"],
  persistence: {MyApp.DbPersistence, []}
)