Add beforeBreadcrumb hook description

Author: tustanivsky

docs/platforms/unreal/configuration/options.mdx

@@ -103,6 +103,19 @@ By the time <PlatformIdentifier name="before-send" /> is executed, all scope dat
 
 </ConfigKey>
 
+<ConfigKey name="before-breadcrumb">
+
+This function is called with an SDK-specific breadcrumb object before the breadcrumb is added to the scope. When nothing is returned from the function, the breadcrumb is dropped. To pass the breadcrumb through, return the first argument, which contains the breadcrumb object.
+The callback typically gets a second argument (called a "hint") which contains the original object from which the breadcrumb was created to further customize what the breadcrumb should look like.
+
+<Alert>
+
+Currently, hints are supported only on Android.
+
+</Alert>
+
+</ConfigKey>
+
 ## Tracing Options
 
 <ConfigKey name="traces-sample-rate">

docs/platforms/unreal/enriching-events/breadcrumbs/index.mdx

@@ -37,3 +37,29 @@ The same result can be achieved by calling corresponding function in blueprint:
 The Unreal Engine SDK can capture certain types of breadcrumbs automatically. Those can be enabled using the Sentry configuration window at **Project Settings > Plugins > Sentry**.
 
 ![Sentry automatic breadcrumbs](./img/unreal_automatic_breadcrumbs.png)
+
+## Customize Breadcrumbs
+
+SDKs allow you to customize breadcrumbs through the <PlatformIdentifier name="before-breadcrumb" /> hook (the corresponding handler class can be set in the plugin settings).
+
+This hook is passed an already assembled breadcrumb and, in some SDKs, an optional hint. The function can modify the breadcrumb or decide to discard it entirely by returning `nullptr`:
+
+```cpp
+UCLASS()
+class UCustomBeforeBreadcrumbHandler : public USentryBeforeBreadcrumbHandler
+{
+	GENERATED_BODY()
+
+public:
+	virtual USentryBreadcrumb* HandleBeforeBreadcrumb_Implementation(USentryBreadcrumb* Breadcrumb, USentryHint* Hint)
+    {
+        if (Breadcrumb->GetCategory() == "Spammy.Logger")
+        {
+            // Discard breadcrumb
+            return nullptr;
+        }
+
+        return Breadcrumb;
+    }
+};
+```