public UpdateRdsDbInstanceRequest withDbUser(String dbUser) {
        setDbUser(dbUser);
        return this;
    }
<p>
The master user name.
</p>

@param dbUser
       The master user name.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-opsworks/src/main/java/com/amazonaws/services/opsworks/model/UpdateRdsDbInstanceRequest.java