Improve the file response performance

Signed-off-by: Jianhui Zhao <zhaojh329@gmail.com>

src/buffer

@@ -1 +1 @@
-Subproject commit 84e1b93c110b8a886fadab0563319506edb66741
+Subproject commit 1bd1b6d192eda9e5bc24582e7ef3a4a017f9b064

src/connection.c

@@ -66,6 +66,7 @@ static void conn_send_file(struct uh_connection *conn, const char *path)
 {
     struct uh_connection_internal *conni = (struct uh_connection_internal *)conn;
     struct stat st;
+    int ret;
 
     conni->file.fd = open(path, O_RDONLY);
 
@@ -73,6 +74,10 @@ static void conn_send_file(struct uh_connection *conn, const char *path)
 
     conni->file.size = st.st_size;
 
+    /* If the file is not greater than 8K, then append it to the HTTP head, send once */
+    ret = buffer_put_fd(&conni->wb, conni->file.fd, 8192, NULL);
+    conni->file.size -= ret;
+
     ev_io_start(conni->srv->loop, &conni->iow);
 }