public com.google.protobuf.ByteString getCredentialsSecretBytes() {
        java.lang.Object ref = credentialsSecret_;
        if (ref instanceof String) {
          com.google.protobuf.ByteString b =
              com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
          credentialsSecret_ = b;
          return b;
        } else {
          return (com.google.protobuf.ByteString) ref;
        }
      }
<pre>
Optional. The Resource name of a secret in Secret Manager.

AWS credentials must be stored in Secret Manager in JSON format:

{
 "access_key_id": "ACCESS_KEY_ID",
 "secret_access_key": "SECRET_ACCESS_KEY"
}

[GoogleServiceAccount][google.storagetransfer.v1.GoogleServiceAccount] must
be granted `roles/secretmanager.secretAccessor` for the resource.

See [Configure access to a source: Amazon S3]
(https://cloud.google.com/storage-transfer/docs/source-amazon-s3#secret_manager)
for more information.

If `credentials_secret` is specified, do not specify
[role_arn][google.storagetransfer.v1.AwsS3Data.role_arn] or
[aws_access_key][google.storagetransfer.v1.AwsS3Data.aws_access_key].

Format: `projects/{project_number}/secrets/{secret_name}`
</pre>

<code>string credentials_secret = 7 [(.google.api.field_behavior) = OPTIONAL];</code>

@return The bytes for credentialsSecret.
java-storage-transfer/proto-google-cloud-storage-transfer-v1/src/main/java/com/google/storagetransfer/v1/proto/TransferTypes.java