fixed a few checks around alt-svc which weren't working:

* alt-svc connection is idle, no IO available, take that into account
when matching;
* we now merge connections when alt-svc'ing, so no need to purge and
send requests, just purge;
* URI's weren't matching well for altsvc, as they were testing if the
URIs were the same, not its origins;
* do not force h2 negotiation when opening alt-svc connection; this
is a trade-off to make it all work for now, as when connecting to an
h2-enabled alt service and we don't support h2 (like in ruby 2.1), we'll
still get an SSL HTTP/1.1 alt service

lib/httpx/connection.rb

@@ -87,7 +87,7 @@ module HTTPX
           # was the result of coalescing. To prevent blind trust in the case where the
           # origin came from an ORIGIN frame, we're going to verify the hostname with the
           # SSL certificate
-          (@origins.size == 1 || @origin == uri.origin || @io.verify_hostname(uri.host))
+          (@origins.size == 1 || @origin == uri.origin || (@io && @io.verify_hostname(uri.host)))
         ) || match_altsvcs?(uri)
       ) && @options == options
     end
@@ -130,7 +130,7 @@ module HTTPX
     def purge_pending
       [@parser.pending, @pending].each do |pending|
         pending.reject! do |request, *args|
-          yield(request, args)
+          yield(request, args) if block_given?
         end
       end
     end

lib/httpx/extensions.rb

@@ -67,10 +67,11 @@ module HTTPX
 
       def altsvc_match?(uri)
         uri = URI.parse(uri)
-        self == uri || begin
+
+        origin == uri.origin || begin
           case scheme
-          when 'h2'
-            uri.scheme == "https" &&
+          when "h2"
+            (uri.scheme == "https" || uri.scheme == "h2") &&
             host == uri.host &&
             (port || default_port) == (uri.port || uri.default_port)
           else

lib/httpx/io/ssl.rb

@@ -30,7 +30,7 @@ module HTTPX
 
     def verify_hostname(host)
       return false if @ctx.verify_mode == OpenSSL::SSL::VERIFY_NONE
-      return false if @io.peer_cert.nil?
+      return false if !@io.respond_to?(:peer_cert) || @io.peer_cert.nil?
 
       OpenSSL::SSL.verify_certificate_identity(@io.peer_cert, host)
     end

lib/httpx/session.rb

@@ -93,15 +93,12 @@ module HTTPX
       # incidentally, all requests will be re-routed to the first
       # advertised alt-svc, which incidentally follows the spec.
       existing_connection.purge_pending do |request|
-        is_idle = request.origin == origin &&
-                  request.state == :idle &&
-                  !request.headers.key?("alt-used")
-        if is_idle
-          log(level: 1) { "#{origin} alt-svc: sending #{request.uri} to #{alt_origin}" }
-          connection.send(request)
-        end
-        is_idle
+        request.origin == origin &&
+          request.state == :idle &&
+          !request.headers.key?("alt-used")
       end
+
+      connection.merge(existing_connection)
     rescue UnsupportedSchemeError
       altsvc["noop"] = true
     end
@@ -137,10 +134,7 @@ module HTTPX
         case uri.scheme
         when "http"
           "tcp"
-        when "https"
-          "ssl"
-        when "h2"
-          options = options.merge(ssl: SSL::TLS_OPTIONS)
+        when "https", "h2"
           "ssl"
         else
           raise UnsupportedSchemeError, "#{uri}: #{uri.scheme}: unsupported URI scheme"