StringMapConverter: set buffer size back to 512 (was 10).

Author: greenrobot-team

objectbox-java/src/main/java/io/objectbox/converter/StringMapConverter.java

@@ -18,7 +18,7 @@ public byte[] convertToDatabaseValue(Map<String, String> map) {
         if (map == null) return null;
 
         FlexBuffersBuilder builder = new FlexBuffersBuilder(
-                new ArrayReadWriteBuf(),
+                new ArrayReadWriteBuf(512),
                 FlexBuffersBuilder.BUILDER_FLAG_SHARE_KEYS_AND_STRINGS
         );
         int mapStart = builder.startMap();