title: telethon GetParticipantsRequest: why returning not all members
body: <p><strong>telethon GetParticipantsRequest</strong>: why returning not all members ?
  For example, my groups has <strong>3377</strong> members, but GetParticipantsRequest return <strong>3356</strong> members.</p>
  <pre><code>while True:
      participants = await client(GetParticipantsRequest(
          my_channel, ChannelParticipantsSearch(''), offset, limit,
          hash=0
      ))
      if not participants.users:
          break
      all_participants.extend(participants.users)
      offset += len(participants.users)
  </code></pre>
  <p>If print <strong>participants</strong>:</p>
  <pre><code>if not participants.users:
      print(participants)
      break
  </code></pre>
  <p>I get:</p>
  <pre><code>ChannelParticipants(count=3389, participants=[], chats=[], users=[])
  </code></pre>
  <p>count=<strong>3389</strong> and it's not equals <strong>3377</strong> (count of members in my group).
  <br/>Why???
  <br/><br/>Plese help me with it.</p>