class_docstr: Wrapper around an AdjustedArrayWindow which supports monotonically
  increasing (by datetime) requests for a sized window of data.
  
  Parameters
  ----------
  window : AdjustedArrayWindow
     Window of pricing data with prefetched values beyond the current
     simulation dt.
  cal_start : int
     Index in the overall calendar at which the window starts.
class_docstr_tok: ["Wrapper","around","an","AdjustedArrayWindow","which","supports","monotonically","increasing","(","by","datetime",")","requests","for","a","sized","window","of","data",".","Parameters","--","--","--","--","--","window",":","AdjustedArrayWindow","Window","of","pricing","data","with","prefetched","values","beyond","the","current","simulation","dt",".","cal_start",":","int","Index","in","the","overall","calendar","at","which","the","window","starts","."]
code: def __init__(self, window, size, cal_start, offset):
      self.window = window
      self.cal_start = cal_start
      self.current = next(window)
      self.offset = offset
      self.most_recent_ix = self.cal_start + size
  
imports: from abc import ABCMeta, abstractmethod, abstractproperty
  from numpy import concatenate
  from lru import LRU
  from pandas import isnull
  from pandas.tslib import normalize_date
  from toolz import sliding_window
  from six import with_metaclass
  from catalyst.assets import Equity, Future
  from catalyst.assets.continuous_futures import ContinuousFuture
  from catalyst.lib._int64window import AdjustedArrayWindow
  from catalyst.lib._float64window import AdjustedArrayWindow
  from catalyst.lib.adjustment import Float64Multiply, Float64Add
  from catalyst.utils.cache import ExpiringCache
  from catalyst.utils.math_utils import number_of_decimal_places
  from catalyst.utils.memoize import lazyval
  from catalyst.utils.numpy_utils import float64_dtype
  from catalyst.utils.pandas_utils import find_in_sorted_index
label_desc: Use image node_id 1 to create a new SlidingWindow object from inherited base classes: object with example: obj = SlidingWindow(window, size, cal_start, offset)