Getting fields parsed so far on parser error #1121

Is there a way to get everything parsed so far (kind of like Probe() does) when an error is raised during parsing?
Simple example of what I am looking for:

import construct as cs

Test = cs.Struct(
    "a" / cs.Byte,
    "b" / cs.Byte,
)

try:
    # Only one byte in input
    result = Test.parse(b"1")
except Exception as e:
    print(e.parsed_so_far)

This would print

Container: 
    a = 49

I looked around the codebase, and the exceptions raised currently don't contain this information. Maybe there is some other way?