title: Number of time steps in one iteration of RLlib training
body: <p>I am new to reinforcement learning and I am working on the RL of a custom environment in OpenAI gym with RLlib. When I create a custom environment, do I need to specify the number of episodes in the <code>__init__()</code> method? ALso, when I train the agent with </p>
  
  <pre><code>for _ in range(10):
       trainer.train()
  </code></pre>
  
  <p>how many time steps are taken in one iteration? is it equal to number of episodes defined in the custom environment? Thank you. </p>