DOCSP-48421-clarify-verifier-lag-time (mongodb#673)

* DOCSP-48421-clarify-verifier-lag-time

* build error

* reviewer update

* fix render

(cherry picked from commit 3fb8e0b)

Author: amalhotra-mdb

source/includes/api/tables/progress-response.rst

@@ -53,6 +53,17 @@
        writes on the source cluster. The time difference becomes zero
        when ``mongosync`` commits the migration.
 
+       With the introduction of the :ref:`embdedded verfier<c2c-embedded-verifier>`
+       in version 1.9, there are three different ``lagTimeSeconds`` fields whenever
+       embedded verification is enabled: 
+       
+       - ``lagTimeSeconds`` for ``mongosync``
+       - ``lagTimeSeconds`` for the source cluster for the verifier
+       - ``lagTimeSeconds`` for the destination cluster for the verifier
+
+       When embdedded verification is disabled, ``lagTimeSeconds`` only applies
+       to ``mongosync``.
+
    * - ``totalEventsApplied``
      - integer
      - The approximate number of change events this instance of 

source/reference/api/commit.txt

@@ -36,7 +36,9 @@ Before using the ``commit`` endpoint:
 - Use the :ref:`progress <c2c-api-progress>` endpoint to confirm the
   following values:
 
-  - ``lagTimeSeconds`` is near ``0`` (*Recommended, but not required*)
+  - ``lagTimeSeconds`` for ``mongosync``, the source cluster 
+    for the verifier, and the destination cluster for the 
+    verifier are all near ``0`` (*Recommended, but not required*)
 
     .. note:: lagTimeSeconds
 
@@ -49,6 +51,9 @@ Before using the ``commit`` endpoint:
        When ``lagTimeSeconds`` is ``0``, the source and destination
        clusters are in a consistent state.
 
+       For more information on the ``lagTimeSeconds`` fields, see
+       :ref:`c2c-api-progress`.
+
   - ``state: "RUNNING"``
   - ``canCommit: true``