Add both bytes and items sizes to the persistent metadata

Signed-off-by: Bogdan Drutu <[email protected]>

Author: bogdandrutu

exporter/exporterhelper/internal/queue/meta.proto

@@ -11,13 +11,14 @@ enum SizerType {
   BYTES = 2;
 }
 
-// QueueMetadata holds all persistent metadata for the queue.
-message QueueMetadata{
-  // Sizer type configuration.
-  SizerType sizer_type = 1;
-
-  // Current total size of the queue (in bytes, items, or requests).
-  sfixed64 queue_size = 2;
+// PersistentMetadata holds all persistent metadata for the queue.
+// The items and bytes sizes are recorded explicitly, the requests size can be calculated as (write_index - read_index).
+message PersistentMetadata{
+  // Current total items size of the queue.
+  sfixed64 items_size = 1;
+
+  // Current total bytes size of the queue.
+  sfixed64 bytes_size = 2;
 
   // Index of the next item to be read from the queue.
   fixed64 read_index = 3;