TODO for DBIx::Threaded:

Test w/ more (many more!) DBDs

Test array binding methods

Test driver-specific functions

Test chained DBI subclasses

Support install_method() in client stub

Better trace() support

Optimize marshal/unmarshal buffers for common
cases (ie, each client stmt stub creates a 
local shared row buffer and passes it to
the server side to be filled)

Finish more_results() support

Build helper classes for true async i/f to DBDs that support such

Figure out how to get this working w/ Apache::DBI