session-android/res/drawable/conversation_item_sent_indicator_text_shape.xml

<?xml version="1.0" encoding="UTF-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

    <item>
        <shape  android:shape="rectangle">
            <solid android:color="#0d000000" />
            <corners android:radius="@dimen/message_bubble_corner_radius" />
        </shape>
    </item>

    <item android:bottom="@dimen/message_bubble_shadow_distance">
        <shape xmlns:android="http://schemas.android.com/apk/res/android">
            <solid android:color="#fff3f3f3" />
            <corners android:bottomLeftRadius="@dimen/message_bubble_corner_radius" android:bottomRightRadius="@dimen/message_bubble_corner_radius" />
        </shape>
    </item>

</layer-list>