add migration docs for client options

Author: AbhiPrasad

CHANGELOG.md

@@ -20,6 +20,7 @@
 - chore: Remove tslint from `@sentry-internal/typescript` (#4940)
 - feat: Add client report hook to makeTransport (#5008)
 - ref(build): Switch tsconfig target to es6 (#5005)
+- ref(core): Make event processing log warnings (#5010)
 - fix(hub): Add missing parameter to captureException docstring (#5001)
 - fix(serverless): Adjust v6 Lambda layer hotfix for v7 (#5006)
 - fix(tracing): Adjust sideEffects package.json entry for v7 (#4987)

MIGRATION.md

@@ -32,6 +32,44 @@ import {
 } from '@sentry/minimal';
 ```
 
+## Explicit Client Options
+
+In v7, we've updated the `Client` to have options seperate from the options passed into `Sentry.init`. This means that constructing a client now requires 3 options: `integrations`, `transport` and `stackParser`. These can be customized as you see fit.
+
+```ts
+import { BrowserClient, defaultStackParsers, defaultIntegrations, makeFetchTransport } from '@sentry/browser';
+import { stackParserFromOptions } from '@sentry/utils';
+
+// New in v7:
+const client = BrowserClient({
+  transport: makeFetchTransport,
+  stackParser: stackParserFromOptions(defaultStackParsers),
+  integrations: [...defaultIntegrations],
+});
+
+// Before:
+const client = BrowserClient();
+```
+
+Since you now explicitly pass in the dependencies of the client, you can also tree-shake out dependencies that you do not use this way. For example, you can tree-shake out the SDK's default integrations and only use the ones that you want like so:
+
+```ts
+import { BrowserClient, defaultStackParsers, Integrations, makeFetchTransport } from '@sentry/browser';
+import { stackParserFromOptions } from '@sentry/utils';
+
+// New in v7:
+const client = BrowserClient({
+  transport: makeFetchTransport,
+  stackParser: stackParserFromOptions(defaultStackParsers),
+  integrations: [
+    new Integrations.Breadcrumbs(),
+    new Integrations.GlobalHandlers(),
+    new Integrations.LinkedErrors(),
+    new Integrations.Dedupe(),
+  ],
+});
+```
+
 ## Removal Of Old Platform Integrations From `@sentry/integrations` Package
 
 The following classes will be removed from the `@sentry/integrations` package and can no longer be used: