code: def step_async(self, actions):
      for remote, action in zip(self.remotes, actions):
          remote.send(("step", action))
      self.waiting = True
  
file_path: keras-rl/rl/common/vec_env/subproc_env_vec.py
imports: import numpy
  from multiprocessing import Process, Pipe
  from rl.common.vec_env import VecEnv, CloudpickleWrapper
  from rl.common.tile_images import tile_images
label_desc: Use image node_id 2 for calling the SubprocVecEnv obj's underlying member method code with example usage: obj.step_async(actions) without return types