+# HTTP request builder
+#
+# The request itself is sent by either `execute` or `download_to_file`.
+# The attributes of this class must be set before calling either of these two methods.
+#
+# ## Minimal usage example
+#
+# ~~~
+# var request = new CurlHTTPRequest("http://example.org/")
+# var response = request.execute
+# if response isa CurlResponseSuccess then
+# print "Response status code: {response.status_code}"
+# print response.body_str
+# else if response isa CurlResponseFailed then
+# print_error response.error_msg
+# end
+# ~~~