fd/fmt: Correct write call

Change-Id: I8ad4682fdbc3754f8bdbf0d6de52d0ab49b1efa0
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/src/fd/fmt.cpp b/src/fd/fmt.cpp
index 217949d..51fdcb1 100644
--- a/src/fd/fmt.cpp
+++ b/src/fd/fmt.cpp
@@ -22,7 +22,7 @@
 {
     if (buf.size() > 0)
     {
-        stdplus::fd::write(fd, buf);
+        stdplus::fd::writeExact(fd, buf);
         buf.clear();
     }
 }