public Loader addMetadataLogDir(String metadataLogDir) {
            if (this.metadataLogDir.isPresent()) {
                throw new RuntimeException("Cannot specify more than one metadata log directory. " +
                    "Already specified " + this.metadataLogDir.get());
            }
            this.metadataLogDir = Optional.of(metadataLogDir);
            logDirs.add(metadataLogDir);
            return this;
        }
Utility class for loading a MetaPropertiesEnsemble from the disk.
metadata/src/main/java/org/apache/kafka/metadata/properties/MetaPropertiesEnsemble.java