DEBUGGING constant

[MadcapJake]

Since DEBUGGING is set in a constant, it only checks for the environment variable at compile time. Thus it's impossible to turn this on or off it only checks once for HST_DEBUG when installing the module.

Perhaps just stick it in a regular variable or you could probably make it a constant sub.

[tokuhirom]

It's a variable for HTTP::Server::Tiny's author. It removes in compiling for performance reason.

[MadcapJake]

Somehow though it was on for me, I couldn't turn it off without changing the constant to a sub. At some point I did have HST_DEBUG set but then unsetting it did nothing to remove the debugging log messages.