Add http simple server script (for benchmarking)

examples/io/http_simple_server.rb

@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require 'bundler/setup'
+require 'polyphony'
+
+PORT = 9090
+
+server = TCPServer.open('127.0.0.1', PORT)
+puts "pid #{Process.pid} Polyphony (#{Thread.current.backend.kind}) listening on port #{PORT}"
+
+# spin_loop(interval: 1) do
+#   p Thread.current.fiber_scheduling_stats
+# end
+
+@max = 0
+@count = 0
+
+def handle_close(client)
+  t0 = monotonic_clock_time
+  spin do
+    client.recv(1024)
+    t1 = monotonic_clock_time
+    client.send("HTTP/1.1 204 No Content\r\nConnection: close\r\n\r\n",0)
+
+    elapsed = t1 - t0
+    @max = elapsed if elapsed > @max
+    @count += 1
+    if @count % 1000 == 0
+      puts "max send latency: #{@max}"
+    end
+    client.close
+  end
+end
+
+def monotonic_clock_time
+  Process.clock_gettime(Process::CLOCK_MONOTONIC)
+end
+
+max = 0
+t0 = monotonic_clock_time
+count = 0
+while (client = server.accept)
+  t1 = monotonic_clock_time
+  elapsed = t1 - t0
+  max = elapsed if elapsed > max
+  count += 1
+  if count % 1000 == 0
+    puts "max accept latency: #{@max}"
+  end
+  handle_close(client)
+end
+
+# server.accept_loop do |client|
+#   spin do
+#     loop do
+#       client.recv(1024)
+#       client.send("HTTP/1.1 200 OK\r\nContent-Length: 14\r\n\r\nHello, world!\n",0)
+#     end
+#   rescue SystemCallError
+#     # ignore
+#   end
+# end