public void setReadMarkerTimestamp(java.util.Date readMarkerTimestamp) {
        this.readMarkerTimestamp = readMarkerTimestamp;
    }
<p>
The time at which an <code>AppInstanceUser</code> last marked a channel as read.
</p>

@param readMarkerTimestamp
       The time at which an <code>AppInstanceUser</code> last marked a channel as read.
aws-java-sdk-chimesdkmessaging/src/main/java/com/amazonaws/services/chimesdkmessaging/model/AppInstanceUserMembershipSummary.java