$data = '';
Benchmark: timing 1000000 iterations of map_split, regex, simple_split...
 map_split:  0 wallclock secs ( 0.99 usr +  0.00 sys =  0.99 CPU) @ 1009081.74/s (n=1000000)
     regex:  1 wallclock secs ( 0.54 usr +  0.00 sys =  0.54 CPU) @ 1848428.84/s (n=1000000)
simple_split:  0 wallclock secs ( 0.94 usr +  0.00 sys =  0.94 CPU) @ 1062699.26/s (n=1000000)