feat: Add Android launch time instrumentation

This commit introduces automatic instrumentation for Android application launch times. It measures and reports two key metrics:
- Time to Initial Display (TTID)
- Time to Full Display (TTFD)

The instrumentation classifies launches as `cold`, `warm`, or `hot` and records the durations as histogram metrics (`app.launch.duration.ttid` and `app.launch.duration.ttfd`). These metrics include attributes for the launch type and the specific activity being launched.

The implementation also includes:
- Adding a dependency on `androidx.activity`.
- Updating the Android compile SDK version to 36 (Required for the dependency added)

Author: agrognetti

e2e/android/app/build.gradle.kts

@@ -7,7 +7,7 @@ plugins {
 
 android {
     namespace = "com.example.androidobservability"
-    compileSdk = 35
+    compileSdk = 36
 
     defaultConfig {
         applicationId = "com.example.androidobservability"

sdk/@launchdarkly/observability-android/lib/build.gradle.kts

@@ -23,6 +23,9 @@ dependencies {
     implementation("com.launchdarkly:launchdarkly-android-client-sdk:5.9.0")
     implementation("com.jakewharton.timber:timber:5.0.1")
 
+    // Android
+    implementation("androidx.activity:activity:1.11.0")
+
     // Coroutines
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.10.2")
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.10.2")
@@ -69,7 +72,7 @@ tasks.withType<Test> {
 
 android {
     namespace = "com.launchdarkly.observability"
-    compileSdk = 35
+    compileSdk = 36
 
     buildFeatures {
         buildConfig = true

sdk/@launchdarkly/observability-android/lib/src/main/kotlin/com/launchdarkly/observability/client/InstrumentationManager.kt

@@ -76,7 +76,7 @@ class InstrumentationManager(
         private const val BATCH_SCHEDULE_DELAY_MS = 1000L
         private const val BATCH_EXPORTER_TIMEOUT_MS = 5000L
         private const val BATCH_MAX_EXPORT_SIZE = 10
-        private const val METRICS_EXPORT_INTERVAL_SECONDS = 10L
+        private const val METRICS_EXPORT_INTERVAL_MS = 10_000L
         private const val FLUSH_TIMEOUT_SECONDS = 5L
     }
 
@@ -135,6 +135,13 @@ class InstrumentationManager(
         otelMeter = otelRUM.openTelemetry.meterProvider.get(INSTRUMENTATION_SCOPE_NAME)
         otelLogger = otelRUM.openTelemetry.logsBridge.get(INSTRUMENTATION_SCOPE_NAME)
         otelTracer = otelRUM.openTelemetry.tracerProvider.get(INSTRUMENTATION_SCOPE_NAME)
+
+        if (!options.disableTraces) {
+            LaunchTimeInstrumentation(
+                application = application,
+                metricRecorder = this::recordHistogram
+            )
+        }
     }
 
     private fun createOtelRumConfig(): OtelRumConfig {
@@ -277,7 +284,7 @@ class InstrumentationManager(
     private fun createPeriodicMetricReader(metricExporter: MetricExporter): PeriodicMetricReader {
         // Configure a periodic reader that pushes metrics every 10 seconds.
         return PeriodicMetricReader.builder(metricExporter)
-            .setInterval(METRICS_EXPORT_INTERVAL_SECONDS, TimeUnit.SECONDS)
+            .setInterval(METRICS_EXPORT_INTERVAL_MS, TimeUnit.MILLISECONDS)
             .build()
     }