passing different request Headers per each request from an external file

[gunayus]

Is it possible to pass different (random) request Headers per each http request from an external file? if not, would you like to add this feature?

my use case is following, I would like to load test my application but for different user accounts in order to eliminate non-realistic cache hits. my app expects 'Authorization' request header to identify the end user.

[codesenberg]

Somewhat similar to #55 I think, but the answer is the same for this FR.