Add Bugsnag.isStarted

bugsnag-android-core/src/main/java/com/bugsnag/android/Bugsnag.java

@@ -69,6 +69,15 @@ public static Client start(@NonNull Context androidContext, @NonNull Configurati
         return client;
     }
 
+    /**
+     * Returns true if one of the <code>start</code> methods have been has been called and
+     * so Bugsnag is initialized; false if <code>start</code> has not been called and the
+     * other methods will throw IllegalStateException.
+     */
+    public static boolean isStarted() {
+        return client != null;
+    }
+
     private static void logClientInitWarning() {
         getClient().logger.w("Multiple Bugsnag.start calls detected. Ignoring.");
     }

bugsnag-android-core/src/test/java/com/bugsnag/android/BugsnagApiTest.kt

@@ -37,6 +37,17 @@ class BugsnagApiTest {
         verify(client, times(1)).context = "Bar"
     }
 
+    @Test
+    fun isStartedWhenStarted() {
+        assertEquals(true, Bugsnag.isStarted())
+    }
+
+    @Test
+    fun isStartedWhenNotStarted() {
+        Bugsnag.client = null
+        assertEquals(false, Bugsnag.isStarted())
+    }
+
     @Test
     fun getUser() {
         Bugsnag.getUser()