class_docstr: Window operator
  
  inputs: ---1-2-3-4-5-6--->
  
  node definition:
  
    [    window_all('input', 'output', callable=lambda i: sum(i))     ]
  
  step:
  
    callable([1, 2, 3, 4, 5, 6]) -> 21
  
  outputs:
    ----21---->
code: def _get_buffer(self):
      ret = dict((key, []) for key in self._node_repr.inputs)
      while True:
          data = self.input_que.get_dict()
          if data is None:
              return ret
  
          if not self.side_by_to_next(data):
              return None
  
          for key in self._node_repr.inputs:
              if data.get(key) is not Empty():
                  ret[key].append(data.get(key))
  
file_path: towhee/towhee/runtime/nodes/_window_all.py
imports: from towhee.runtime.data_queue import Empty
  from towhee.runtime.time_profiler import Event
  from .node import Node
  from ._single_input import SingleInputMixin
label_desc: Use image node_id 1 for calling the WindowAll obj's underlying member method code with example usage: obj._get_buffer() and returns: ret, None