Crawler example clears the response before each read:

fix #1100

Unfortunately the example still seems to hang, tested
with 20 threads.

CHANGELOG.md

@@ -1,6 +1,7 @@
 Version 197:
 
 * Improvements to echo-op example
+* Crawler example clears the response before each read
 
 --------------------------------------------------------------------------------
 

example/http/client/crawl/http_crawl.cpp

@@ -337,6 +337,7 @@ public:
         timer_.expires_after(chrono::seconds(timeout));
 
         // Receive the HTTP response
+        res_ = {};
         http::async_read(
             socket_,
             buffer_,