odirect_write.c: Resolve unused variable "total_size"

Symptom with Clang 17:
> tests/odirect_write.c:35:12: warning: variable 'total_size' set but not used [-Wunused-but-set-variable]
>    35 |     size_t total_size = 0;
>       |            ^

1 files changed, 0 insertions, 3 deletions

diff --git a/tests/odirect_write.c b/tests/odirect_write.c
index 626ff5c..11dde43 100644
--- a/tests/odirect_write.c
+++ b/tests/odirect_write.c
@@ -32,7 +32,6 @@ int main(int argc, char** argv) {
         return 1;
     }
 
-    size_t total_size = 0;
     while (1) {
         if (feof(stdin)) {
             break;
@@ -48,8 +47,6 @@ int main(int argc, char** argv) {
             continue;
         }
 
-        total_size += amt_read;
-
         ssize_t res = write(fd, buf, buf_size);
         if (res == -1) {
             perror("failed to write");