bugfix: prevent stream close callback from being called 2 times

an issue was observed when stream was closed from our side, that the
the request in-flight count on the connection. This was fixed by not
reacting to :stream_closed events if request has been previously deleted.

lib/httpx/connection.rb

@@ -412,7 +412,8 @@ module HTTPX
         AltSvc.emit(request, response) do |alt_origin, origin, alt_params|
           emit(:altsvc, alt_origin, origin, alt_params)
         end
-        handle_response
+        @response_received_at = Utils.now
+        @inflight -= 1
         request.emit(:response, response)
       end
       parser.on(:altsvc) do |alt_origin, origin, alt_params|
@@ -516,11 +517,6 @@ module HTTPX
       remove_instance_variable(:@timeout) if defined?(@timeout)
     end
 
-    def handle_response
-      @response_received_at = Utils.now
-      @inflight -= 1
-    end
-
     def on_error(error)
       if error.instance_of?(TimeoutError)
 

lib/httpx/connection/http2.rb

@@ -291,11 +291,13 @@ module HTTPX
     end
 
     def on_stream_refuse(stream, request, error)
-      stream.close
       on_stream_close(stream, request, error)
+      stream.close
     end
 
     def on_stream_close(stream, request, error)
+      return if error == :stream_closed && !@streams.key?(request)
+
       log(level: 2) { "#{stream.id}: closing stream" }
       @drains.delete(request)
       @streams.delete(request)

sig/connection.rbs

@@ -93,8 +93,6 @@ module HTTPX
 
     def transition: (Symbol) -> void
 
-    def handle_response: () -> void
-
     def on_error: (HTTPX::TimeoutError | Error | StandardError) -> void
 
     def handle_error: (StandardError) -> void