Add PR reviews metrics.

Adds two new metrics:

- `NumberOfPRReviewDiffViewInlineCommentStartReview`: incremented when the "Start Review" button is clicked from an inline comment
- `NumberOfPRReviewPosts`: incremented when a PR review is submitted

Author: grokys

src/GitHub.Exports/Models/UsageModel.cs

@@ -42,6 +42,8 @@ public struct UsageModel
         public int NumberOfPRDetailsNavigateToEditor { get; set; }
         public int NumberOfPRReviewDiffViewInlineCommentOpen { get; set; }
         public int NumberOfPRReviewDiffViewInlineCommentPost { get; set; }
+        public int NumberOfPRReviewDiffViewInlineCommentStartReview { get; set; }
+        public int NumberOfPRReviewPosts { get; set; }
         public int NumberOfShowCurrentPullRequest { get; set; }
 
         public UsageModel Clone(bool includeWeekly, bool includeMonthly)

src/GitHub.InlineReviews/Services/PullRequestSessionService.cs

@@ -344,7 +344,9 @@ public async Task<IPullRequestReviewModel> CreatePendingReview(
                     User = user,
                 });
 
-            return await graphql.Run(addReview);
+            var result = await graphql.Run(addReview);
+            await usageTracker.IncrementCounter(x => x.NumberOfPRReviewDiffViewInlineCommentStartReview);
+            return result;
         }
 
         /// <inheritdoc/>
@@ -368,6 +370,8 @@ public async Task<IPullRequestReviewModel> PostReview(
                 body,
                 e);
 
+            await usageTracker.IncrementCounter(x => x.NumberOfPRReviewPosts);
+
             return new PullRequestReviewModel
             {
                 Id = result.Id,
@@ -407,7 +411,9 @@ public async Task<IPullRequestReviewModel> SubmitPendingReview(
                     User = user,
                 });
 
-            return await graphql.Run(mutation);
+            var result = await graphql.Run(mutation);
+            await usageTracker.IncrementCounter(x => x.NumberOfPRReviewPosts);
+            return result;
         }
 
         /// <inheritdoc/>
@@ -451,7 +457,9 @@ public async Task<IPullRequestReviewCommentModel> PostPendingReviewComment(
                     IsPending = true,
                 });
 
-            return await graphql.Run(addComment);
+            var result = await graphql.Run(addComment);
+            await usageTracker.IncrementCounter(x => x.NumberOfPRReviewDiffViewInlineCommentPost);
+            return result;
         }
 
         /// <inheritdoc/>
@@ -491,7 +499,9 @@ public async Task<IPullRequestReviewCommentModel> PostPendingReviewCommentReply(
                     IsPending = true,
                 });
 
-            return await graphql.Run(addComment);
+            var result = await graphql.Run(addComment);
+            await usageTracker.IncrementCounter(x => x.NumberOfPRReviewDiffViewInlineCommentPost);
+            return result;
         }
 
         /// <inheritdoc/>