in src/main/java/com/amazonaws/neptune/auth/NeptuneSigV4SignerBase.java [121:125]
public NeptuneSigV4SignerBase(final String regionName,
final AwsCredentialsProvider awsCredentialsProvider) throws NeptuneSigV4SignerException {
// Use neptune-db as default service name
this(regionName, awsCredentialsProvider, NEPTUNE_SERVICE_NAME);
}