code: @Override
    @Deprecated
    public NettyChannelBuilder usePlaintext(boolean skipNegotiation) {
      if (skipNegotiation) {
        negotiationType(NegotiationType.PLAINTEXT);
      } else {
        negotiationType(NegotiationType.PLAINTEXT_UPGRADE);
      }
      return this;
    }
docs: Equivalent to using {@link #negotiationType(NegotiationType)} with {@code PLAINTEXT} or
  {@code PLAINTEXT_UPGRADE}.
  
  @deprecated use {@link #usePlaintext()} instead.