mg_read() does not block on content_len=0. mg_read() reads until socket is closed if content-length is not provided

test/test.pl

@@ -180,7 +180,8 @@ o("GET /dir%20with%20spaces/桌面/ HTTP/1.0\r\n\r\n", 'куку!',
   'Non-ascii chars in path');
 o("GET /hello.txt HTTP/1.1\nConnection: close\nRange: bytes=3-50\r\n\r\n",
   'Content-Length: 15\s', 'Range past the file end');
-o("GET /hello.txt HTTP/1.1\n\n   GET /hello.txt HTTP/1.0\n\n",
+o("GET /hello.txt HTTP/1.1\nContent-Length: 0\n\n   ".
+  "GET /hello.txt HTTP/1.0\nContent-Length: 0\n\n",
   'HTTP/1.1 200.+keep-alive.+HTTP/1.1 200.+close',
   'Request pipelining', 2);