Start collecting data on demand

[rbel.io]

Is your feature request related to a problem? Please describe.
Not sure if this is possible yet, what we noticed is that the vizier pods are storing allot of data almost 3Gb (per pod) right now. Even this is not enough and OomKilled events happens allot.

Describe the solution you'd like
We would like Pixie to start collecting data for a X period only during a debug session for example. After this session it should stop collecting data.

Describe alternatives you've considered
I don't know enough about Pixie to answer this question.

Additional context
NATM

[Ben Kilimnik]

Pixie has the ability to disable tracing for specific protocols via PEM flags see #1669. I believe you could write a bash script to turn tracing off at particular intervals on each PEM.