with (string->blob/shared (string-read ...))

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$ time csi -s extractor.scm
#: 124
0.136s CPU time, 0.028s GC time (major), 27528/4736 mutations (total/tracked), 4/213 GCs (major/minor)

real    0m5.201s
user    0m0.292s
sys     0m0.004s


$ time csi -s extractor.scm
#: 124
0.124s CPU time, 0.032s GC time (major), 27461/4755 mutations (total/tracked), 5/212 GCs (major/minor)

real    0m5.223s
user    0m0.292s
sys     0m0.020s

                                                  
$ time csi -s extractor.scm
#: 124
0.124s CPU time, 0.028s GC time (major), 27486/4763 mutations (total/tracked), 5/212 GCs (major/minor)

real    0m5.230s
user    0m0.308s
sys     0m0.000s
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