In Casablanca release, due to the time window limitation, we implement the policy distribution service  s3p using the filesystemReceptionHandler.

However, there is quite some improvement we can apply for PSSD s3p test:

1. enhance filesystemReceptionHandler to support multi thread: currently, the filesystemReceptionHandler only support single thread, we need to enhance it to support multi thread
2. remove the dependency to pdp/pap: the current pssd s3p test depends on the real environment of policy pdp/pap running. The stability and performance of pdp/pap would affect the test result of pssd s3p test. We need to remove this dependency by implement a new forwarding plugin to inherit existing XacmlPdpPolicyForwarder. The new forwarding plugin log the restful APIs to backend PAP/PDP instead of really sending them out. This way, we can remove the pssd dependency to all other services during S3P test and only focus on the stability/performance of pssd internally itself.

https://gerrit.onap.org/r/#/c/76087/ introduced intentional sleep which would affect performance test, needs to investigate if this race condition exists on linux OS.