diff --git a/mongoose.c b/mongoose.c
index 23eb0b3b..e228f6c8 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -5362,6 +5362,11 @@ static void mg_ev_handler(struct ns_connection *nc, int ev, void *p) {
             write_terminating_chunk(conn);
           }
           close_local_endpoint(conn);
+          /* 
+           * MG_POLL callback returned MG_TRUE,
+           * i.e. data is sent, set corresponding flag 
+           */
+          conn->ns_conn->flags |= NSF_FINISHED_SENDING_DATA;
         }
 
         if (conn->endpoint_type == EP_FILE) {
diff --git a/mongoose.h b/mongoose.h
index a434758d..522e92ad 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -60,7 +60,8 @@ struct mg_connection {
 struct mg_server; // Opaque structure describing server instance
 enum mg_result { MG_FALSE, MG_TRUE, MG_MORE };
 enum mg_event {
-  MG_POLL = 100,  // Callback return value is ignored
+  MG_POLL = 100,  // If callback returns MG_TRUE connection closes
+                  // after all of data is sent
   MG_CONNECT,     // If callback returns MG_FALSE, connect fails
   MG_AUTH,        // If callback returns MG_FALSE, authentication fails
   MG_REQUEST,     // If callback returns MG_FALSE, Mongoose continues with req