How to detect when function is executed in 'upstream' ?
I would like to ignore a second 'next()' call if a previous one was called. Something the following on the second 'next()' in the middleware: 
`if(context.requestFlow != 'upstream') await next()`
(currently I'm getting 'Error: next() called multiple times')
The first 'next()' call is conditionally called. basically implemented dynamic middleware array execution. 
What's my options ?
Thanks 