* implement per-run execute() using system threads, then global execute() can
  just fire off as many threads as there are runs
  - this would allow (re-)sending of individual runs, iterations within a run
  - complications with concurrent request slots: does each thread keep
    its own set of file descriptors, or (sh)(c)ould threads share them?
* need a way to simulate real-world problems: for example
  - slow dialup modem connections
    o e.g. add an automatic delay after each request in a run
    o also support a pre-configured delay inside a run
  - user-presses-stop, aka broken socket
* bring up-to-date with current Apache 2.0 distribution of ab.c
  - including SSL support
* perl subroutine hooks between requests in a sequence, with access
  to all prior regression data and ability to dynamically change current or
  future requests in sequence
* XML configuration files, like Apache's flood project
* more logical object-based configuration; make a single request into an
  object; try to replicate LWP: HTTP::Request and HTTP::Response
* time-limit repeat feature: keep sending requests for NNN seconds