http2 client: fallback to HTTP/1.1 ? or how can a http client library gracefully support both http2 and http1 servers? #16597

I filed nodejs/http2#189 but seems no discussions at all, wonder is it possible for a http client library gracefully support both http2 and http1 servers? I want the client library to prefer connect by http2, then fallback to http1; I've tried current http2.connect but seems unable to connect if a server does not support http2? current behavior of http2.connect("https://some-no-http2-server") is returned a http2session but got destroyed after tried connection; so the solution I can think of is to use a http2session close event listener if closed almost immediately can try fallback to http1; however this won't be efficient; wonder anyone has better ideas?

$ node -p process.versions
{ http_parser: '2.7.0',
  node: '8.8.1',
  v8: '6.1.534.42',
  uv: '1.15.0',
  zlib: '1.2.11',
  ares: '1.10.1-DEV',
  modules: '57',
  nghttp2: '1.25.0',
  openssl: '1.0.2l',
  icu: '59.1',
  unicode: '9.0',
  cldr: '31.0.1',
  tz: '2017b' }