Traffic duplication, can it be done with available software?

[Ulysses_]

Sometimes multiwan is not good enough, one line gets a high latency and delays the completion of a webpage's download and any scripts but the latency is not high enough to deem the line too slow and do the failsafe thing ie use the other line only. (What is the trigger latency?)

Instead of multiwan, there is this possibility:

Traffic duplication […] a newly developed technology that transports mission-critical and other traffic simultaneously over two networks

In other words, a web page could be downloaded twice in parallel from each of the two lines. Trading bandwidth for reliability. Can this be done with anything that pfsense comes with? Or any software that can be downloaded?