Fix imports to avoid failing build
diff --git a/samples/drumthumper/src/main/java/com/google/oboe/samples/drumthumper/DrumThumperActivity.kt b/samples/drumthumper/src/main/java/com/google/oboe/samples/drumthumper/DrumThumperActivity.kt
index d9766fc..d973097 100644
--- a/samples/drumthumper/src/main/java/com/google/oboe/samples/drumthumper/DrumThumperActivity.kt
+++ b/samples/drumthumper/src/main/java/com/google/oboe/samples/drumthumper/DrumThumperActivity.kt
@@ -26,17 +26,10 @@
 import android.widget.LinearLayout
 import android.widget.SeekBar
 import android.widget.Toast
-
 import androidx.appcompat.app.AppCompatActivity
-
-import java.util.*
-
-import java.time.LocalDateTime;
-
 import java.time.LocalDateTime
 import java.util.Timer
 import kotlin.concurrent.schedule
-import kotlin.math.roundToInt
 
 
 class DrumThumperActivity : AppCompatActivity(),