README.md in fluent-plugin-elapsed-time-0.0.2 vs README.md in fluent-plugin-elapsed-time-0.0.3

@@ -19,10 +19,11 @@
 ```apache
 <match **>
   type elapsed_time
   tag elapsed
   interval 60
+  each message
   <store>
     type grep
     exclude foobar
     add_tag_prefix greped
   </store>
@@ -43,22 +44,55 @@
 <match elapsed>
   type stdout
 </match>
 ```
 
-## Option Parameters
+Output will be like
 
-* tag
+```
+elapsed: {"max":1.011,"avg":0.002","num":10}
+```
 
-    The output tag name. Default is `elapsed`
+where `max` and `avg` are the maximum and average elapsed times, and `num` is the number of messages.
 
+## Option Parameters
+
 * interval
 
     The time interval to emit measurement results
 
 * each
 
     Measure time for each `message` or `es` (event stream). Please notice that the event stream (would be a msgpack) will be unpacked if `message` is specified, which would cause performance degradation. Default is `es`.
+
+* tag
+
+    The output tag name. Default is `elapsed`
+
+* add_tag_prefix
+
+    Add tag prefix for output message
+
+* remove_tag_prefix
+
+    Remove tag prefix for output message
+
+* remove_tag_slice *min..max*
+
+    Remove tag parts by slice function. FYI: This option behaves like `tag.split('.').slice(min..max)`.
+
+    For example,
+
+        remove_tag_slice 0..-2
+
+    changes an input tag `foo.bar.host1` to `foo.bar`. 
+
+* aggregate
+
+    Measure and emit outputs for each `tag` or `all`. Default is `all`.
+
+    `all` measures `max` and `avg` for all input messages.
+    `tag` measures `max` and `avg` for each tag *modified* by `add_tag_prefix`, `remove_tag_prefix`, or `remove_tag_slice`. 
 
 ## ChangeLog
 
 See [CHANGELOG.md](CHANGELOG.md) for details.