class_docstr: Abstract class for Replay Buffer.
  
  Args:
      env_spec (EnvSpec): Environment specification.
      size_in_transitions (int): total size of transitions in the buffer
      time_horizon (int): time horizon of epsiode.
code: def __init__(self, env_spec, size_in_transitions, time_horizon):
      del env_spec
      self._current_size = 0
      self._current_ptr = 0
      self._n_transitions_stored = 0
      self._time_horizon = time_horizon
      self._size_in_transitions = size_in_transitions
      self._size = size_in_transitions // time_horizon
      self._initialized_buffer = False
      self._buffer = {}
      self._episode_buffer = {}
  
file_path: garage/src/garage/replay_buffer/replay_buffer.py
imports: import abc
  from abc import abstractmethod
  import numpy
label_desc: Use image node_id 1 to create a new ReplayBuffer object  with example: obj = ReplayBuffer(env_spec, size_in_transitions, time_horizon)