synchronized void addAlias(MimeType type, MediaType alias) {
        registry.addAlias(type.getType(), alias);
    }
Adds an alias for the given media type. This method should only
be called from {@link MimeType#addAlias(String)}.

@param type  media type
@param alias media type alias (normalized to lower case)
tika-core/src/main/java/org/apache/tika/mime/MimeTypes.java