use opt_str_freeze for Hash#delete

Unfortunately we cannot rely on the RubyVM for optimizing hash
deletions, yet, so manually freeze for this string since it
(unlike every line after it) is a hot path if handling request
bodies.

Update a comment while we're at it.

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/yahns/http_response.rb b/lib/yahns/http_response.rb
index 19075bb..b36f696 100644
--- a/lib/yahns/http_response.rb
+++ b/lib/yahns/http_response.rb
@@ -22,7 +22,7 @@ module Yahns::HttpResponse # :nodoc:
     end
   end
 
-  # avoid GC overhead for frequently used-strings:
+  # avoid GC overhead for frequently used-strings/objects:
   CCC_RESPONSE_START = [ 'HTTP', '/1.1 ' ]
 
   # no point in using one without the other, these have been in Linux
@@ -252,7 +252,7 @@ module Yahns::HttpResponse # :nodoc:
   # returns nil on success
   # returns :close, :wait_writable, or :wait_readable
   def http_100_response(env)
-    env.delete("HTTP_EXPECT") =~ /\A100-continue\z/i or return
+    env.delete('HTTP_EXPECT'.freeze) =~ /\A100-continue\z/i or return
     buf = @hs.response_start_sent ? "100 Continue\r\n\r\nHTTP/1.1 ".freeze
                                   : "HTTP/1.1 100 Continue\r\n\r\n".freeze