feat(lander): support sendind extra attributes as custom headers

include/lander.h

@@ -62,4 +62,10 @@ bool lander_remove_entry(event_loop_conn *conn);
 
 bool lander_post_file_lsm(event_loop_conn *conn);
 
+/**
+ * Parse any custom headers and add them as attributes to the context's LSM
+ * entry
+ */
+bool lander_headers_to_attrs(event_loop_conn *conn);
+
 #endif