The man page says
Esxtop in
batch mode runs until it produces the number of iterations requested
(see command-line option n below for more details) or until killed
using CTRL c.
It makes no other mention of signals.
I would try a simple experiment. In another terminal I would run the command again with a different output filename
esxtop –b –a –d 10 –n 2000| gzip -9c > test.csv.gz
I would let it collect data for a short time and hen type Ctrl-c. Inspect the output and see if it is corrupted or not.
You could try a similar experiment by sending a HUP
to the test process.