Encapsulates oai metadataformat xml data
This constructor method returns a new HTTP::OAI::MetadataFormat object. These methods respectively return and optionally set the metadataPrefix, schema and, metadataNamespace, for the metadataFormat record. metadataNamespace is optional in \s-1OAI\s0 1.x and therefore may be undef when harvesting pre \s-1OAI\s0 2 repositories.