minidump: Be consistent about setting the fields of WritableIoVec

minidump/minidump_thread_writer.cc

Index: minidump/minidump_thread_writer.cc
diff --git a/minidump/minidump_thread_writer.cc b/minidump/minidump_thread_writer.cc
index 8f0e0856db120624dbfdc466f5c10355d3c37dfe..e2392322c7fe330b1099fe0ce74802d16b61c626 100644
--- a/minidump/minidump_thread_writer.cc
+++ b/minidump/minidump_thread_writer.cc
@@ -164,8 +164,8 @@ bool MinidumpThreadListWriter::WriteObject(FileWriterInterface* file_writer) {
   std::vector<WritableIoVec> iovecs(1, iov);
 
   for (const MinidumpThreadWriter* thread : threads_) {
-    iov.iov_len = sizeof(MINIDUMP_THREAD);
     iov.iov_base = thread->MinidumpThread();
+    iov.iov_len = sizeof(MINIDUMP_THREAD);
     iovecs.push_back(iov);
   }