@spec execute_for_shape(
  Postgrex.conn(),
  Electric.Shapes.Shape.handle(),
  Electric.Shapes.Shape.t(),
  [
    option
  ]
) :: {:ok, result} | {:error, any()}
when result: term(),
     option:
       {:snapshot_info_fn,
        (Electric.Shapes.Shape.handle(), pg_snapshot, pos_integer() -> any())}
       | {:query_fn, (Postgrex.conn(), pg_snapshot, pos_integer() -> result)}
       | {:stack_id, Electric.stack_id()},
     pg_snapshot:
       {xmin :: pos_integer(), xmax :: pos_integer(),
        xip_list :: [pos_integer()]}

Execute a snapshot query for a shape in a isolated readonly transaction.

This function operates on two callbacks: snapshot_info_fn and query_fn.

snapshot_info_fn is called with the shape handle, the pg_snapshot, and the lsn as soon as the snapshot information for the started transaction is available.

query_fn is called with the connection, the pg_snapshot, and the lsn and is expected to do all the work querying and dealing with the results.

The query function is executed within a transaction, so it shouldn't return a stream (as it will fail to be read after the transaction is committed), but rather should execute all desired side-effects or materialize the results.

Query will be executed within a REPEATABLE READ READ ONLY transaction, with correct display settings set.

Options:

• :query_fn - the function to execute the query.
• :snapshot_info_fn - the function to call with the snapshot information.
• :stack_id - the stack id for this shape.