We are still doing our Exadata migration, apologies for not posting more on this as it progresses but I find it hard to determine what is, and is not acceptable to blog (confidentially, NDA and all that stuff). I'm also quite busy and hardly find the time to blog generally. In any case, we are now on the 3rd environment, that being production support or QA, and have noticed that even though we do not have any Streams configured, we are seeing miscellaneous Streams events as one of the top wait events. It turns out that is not only expected but can be regarded as an idle wait. This happens because we are running GoldenGate Extract with the THREADOPTIONS DBLOGREADER parameter which enables the use of the OCIPOGG module. The wait (OTHER) is being reported while GoldenGate waits for additional logfile data to be made available.
So it would seem with the latest GoldenGate (22.214.171.124) that there is some integration with Streams. This makes sense since they are both Oracle products and per Oracle's Goldengate Statement of Direction GoldenGate is the strategic direction where the best of Streams will be integrated into GoldenGate.
For further information please reference MOS article: "Why do I see Streams Miscellaneous Event in AWR as a top event when Goldengate Extract is running [ID 1317122.1]".