HTTPTupleView Windowing does not support multiple partition keys in a comma-delimited string

[joergboe]

This is observed when parameterizing the "partitionKey" attribute, such
that the key is a comma-delimited string. For example, if "key1,key2"
were directly provided into the operator, then this would be successful
such that two keys are to be partitioned. However, if "$parameterKey"
is provided such that "key1,key2" is passed into $parameterKey, then
only a single partition key will be interpreted; namely, the key that
equals "key1,key2"

We've observed this could be corrected by detecting for embedded
delimiters within following: https://github.com/IBMStreams/streamsx.
inet/blob/master/com.ibm.streamsx.
inet/impl/java/src/com/ibm/streamsx/inet/window/WindowContentsAtTrigger.
java#L55

This issue was reported from a customer. I put this as areminder for further improvements here.

[joergboe]

Release 2.9.5 contains this enhancement.