You could write this off as a library implementation problem, but it comes about because of unfortunate mapping of HTTP parameters to well-known environment variables in CGI, and has tripped up multiple library authors.
I believe the parent comment was thinking of 1 round trip time.
Typically the TCP initial congestion window size is set to 10 packets (RFC 6928), hence ten packets can be sent by the server before waiting for an ACK from the client.
So under 15kB or so (minus TLS certs and the like) website loading has the minimum latency possible given any other network factors.
However, that does not take account of GCP services being implemented behind the scenes using other GCP technologies in Google-managed projects - e.g. Cloud SQL uses Compute Engine and GCR (search "speckle umbrella"). Cloud Functions relies on Cloud Build to compile the function into a container. AI Platform Training uses a GKE cluster internally.
You can often get hints about these things from the VPC-SC documentation, which explains on a per-service basis which APIs need to be enabled to protect the perimeter:
"The Pyramid Principle: Logic in Writing and Thinking" by Barbara Minto.
This approach is taught at consultancy firms to help structure clear written business communication, especially if your audience includes time-poor senior executives.
https://caniuse.com/input-datetime