Bap_strings_scannernext ~is_stop ~read off reads characters starting with the offset off, using the read function to map offsets to characters, until the is_stop character occurs, or the read function returns None.
Postcondition: forall c in result, not (is_stop c)
val run : 
  ?is_stop:(char -> bool) ->
  read:(int -> char option) ->
  int ->
  (int * string) Core_kernel.Sequence.tscan ~is_stop ~read off applies next ~is_stop ~read for all offsets that are bigger than off until read off is not None. Returns a sequence of non-empty strings, paired with their corresponding offsets in data.