docs: add CNAME initialization examples for iOS and Android

CHANGELOG.md

@@ -9,6 +9,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- README examples for configuring a custom CNAME endpoint on iOS (`MPNetworkOptions.customBaseURL`) and Android (`NetworkOptions.withNetworkOptions`).
+
 ## [3.0.1] - 2026-05-27
 
 ### Fixed

README.md

@@ -95,6 +95,20 @@ didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
 }
 ```
 
+Optional: if your team uses a custom CNAME endpoint, configure `MPNetworkOptions` separately:
+
+```swift
+let networkOptions = MPNetworkOptions()
+networkOptions.customBaseURL = URL(string: "https://rkt.example.com")
+mParticleOptions.networkOptions = networkOptions
+```
+
+```objective-c
+MPNetworkOptions *networkOptions = [MPNetworkOptions new];
+networkOptions.customBaseURL = [NSURL URLWithString:@"https://rkt.example.com"];
+mParticleOptions.networkOptions = networkOptions;
+```
+
 Please see [Identity](http://docs.mparticle.com/developers/sdk/ios/identity/) for more information on supplying an `MPIdentityApiRequest` object during SDK initialization.
 
 
@@ -128,6 +142,26 @@ class MyApplication : Application() {
 }
 ```
 
+Optional: if your team uses a custom CNAME endpoint, configure `NetworkOptions` separately:
+
+```java
+import com.mparticle.networking.NetworkOptions;
+
+MParticleOptions options = MParticleOptions.builder(this)
+    .credentials("REPLACE ME WITH KEY", "REPLACE ME WITH SECRET")
+    .networkOptions(NetworkOptions.withNetworkOptions("https://rkt.example.com"))
+    .build();
+```
+
+```kotlin
+import com.mparticle.networking.NetworkOptions
+
+val options = MParticleOptions.builder(this)
+    .credentials("REPLACE ME WITH KEY", "REPLACE ME WITH SECRET")
+    .networkOptions(NetworkOptions.withNetworkOptions("https://rkt.example.com"))
+    .build()
+```
+
 > **Warning:** It's generally not a good idea to log events in your `Application.onCreate()`. Android may instantiate your `Application` class for a lot of reasons, in the background, while the user isn't even using their device.