code: public SslHandler create(ByteBufAllocator bufferAllocator) {
      SSLEngine engine = sslContext.newEngine(bufferAllocator);
      engine.setNeedClientAuth(needClientAuth);
      engine.setUseClientMode(false);
      return new SslHandler(engine);
    }
docs: Creates an SslHandler
  
  @param bufferAllocator the buffer allocator
  @return instance of {@code SslHandler}