Expose PackConfiguration() method

Change-Id: I5a6f1e3555959b798bf35df397d07340cd05791e
Signed-off-by: James Kuszmaul <james.kuszmaul@bluerivertech.com>
diff --git a/aos/events/logging/log_writer.h b/aos/events/logging/log_writer.h
index 114e874..837a02a 100644
--- a/aos/events/logging/log_writer.h
+++ b/aos/events/logging/log_writer.h
@@ -20,6 +20,11 @@
 namespace aos {
 namespace logger {
 
+// Packs the provided configuration into the separate config LogFileHeader
+// container.
+aos::SizePrefixedFlatbufferDetachedBuffer<LogFileHeader> PackConfiguration(
+    const Configuration *const configuration);
+
 // Logs all channels available in the event loop to disk every 100 ms.
 // Start by logging one message per channel to capture any state and
 // configuration that is sent rately on a channel and would affect execution.