Send OBJ_ITER_END only with the last chunk of data

This does not make a difference for HTTP1, and as we only use HTTP1
backends, does not many any difference right now.

src/tus_stv.c

@@ -144,7 +144,7 @@ tus_objiterator(struct worker *wrk, struct objcore *oc,
 	const size_t max_write = 16 * 1024 * 1024;
 	struct tus_concat *c;
 	struct tus_file_core *fcore;
-	unsigned i;
+	unsigned flags, i;
 	size_t off, len;
 	void *p;
 	int r = -1;
@@ -170,20 +170,25 @@ tus_objiterator(struct worker *wrk, struct objcore *oc,
 		AZ(posix_madvise(p, len, POSIX_MADV_SEQUENTIAL));
 		AZ(posix_madvise(p, len, POSIX_MADV_WILLNEED));
 		off = 0;
+		flags = OBJ_ITER_FLUSH;
 		do {
 			len = fcore->len - off;
 			if (len > max_write)
 				len = max_write;
 
 			p = (char *)fcore->ptr + off;
-			r = func(priv, OBJ_ITER_END | OBJ_ITER_FLUSH, p, len);
+			off += len;
+
+			if (off == fcore->len)
+				flags |= OBJ_ITER_END;
+
+			r = func(priv, flags, p, len);
 
 			if (r < 0)
 				return (r);
 
 			AZ(posix_madvise(p, len, POSIX_MADV_DONTNEED));
 
-			off += len;
 		} while (off < fcore->len);
 	}
 	return (r);