Clarify what's the purpose of sending 1 byte

test/test_puma_server_ssl.rb

@@ -83,7 +83,11 @@ def test_url_scheme_for_https
   def test_request_wont_block_thread
     # Open a connection and give enough data to trigger a read, then wait
     socket = TCPSocket.new @host, @port
-    socket.write "x"
+    socket.write "x" # We send a single byte and we'll later close the socket,
+                     # this isn't enough data to process a SSL Client Hello.
+                     # Therefore, this will cause our SSL implementation to try
+                     # to read more from the socket before rejecting the
+                     # connection due to an error in handshake.
     sleep 1
 
     # Capture the amount of threads being used after connecting and being idle