in src/main/java/software/amazon/msk/auth/iam/internals/AWS4SignedPayloadGenerator.java [88:95]
private Aws4PresignerParams createSigningParams(AuthenticationRequestParams params) {
return Aws4PresignerParams.builder()
.awsCredentials(params.getAwsCredentials())
.expirationTime(getExpiry())
.signingRegion(params.getRegion())
.signingName(params.getServiceScope())
.build();
}