elektron refinitiv-realtime eta-api elektron-sdk rrt elektron-transport-api java rssl c++ rcc-api connection source-directory symbology trep batch ssl api log-in fields c Service eikon ETA token linux non-interactive-provider reactor rdm ADS market-by-price market-feed rics callback status consumer DACS elektron-data-dictionary api-limits service-id trade conflation dispatch documentation quote chain-ric search enum open-source service discovery load-balancing compile message commodities ipa snapshot-pricing fanout rdf contributions monitoring failover stream-id aws error build service-name events unsubscribe multi-threading mrn constituents volume time-stamp pricing stale tick-history-rest-api rfa OMM elektron-direct-feed equities refresh-message subscription rcc exchanges sink-driven-source sequence stress-test service-dictionary data-model encoding docker ADH performance 64-bit