public static STSProfileCredentialsServiceLoader getInstance() {
        return INSTANCE;
    }
Loads <code>com.amazonaws.services.securitytoken.internal.STSProfileCredentialsService</code>
from the STS SDK module, if the module is on the current classpath.
aws-java-sdk-core/src/main/java/com/amazonaws/auth/profile/internal/securitytoken/STSProfileCredentialsServiceLoader.java