What is the unit of a read (for a read timeout)?

[konstin]

reqwest offers a read_timeout option, which can be set to avoid the process getting stuck indefinitely while still allowing large downloads to take a long time. I'm trying to figure out what the correct value for a widely deployed CLI application is that often runs in unreliable environments such as GitHub Action. For that I'm wondering, what is the unit of a read, what counts as read? For example, if a read timeout of 10s failed, does this mean that no package was received from the server in the last 10s? Or does it require a specific throughput, e.g. a certain number of KB?

In that context, do we need to set a connect_timeout if we set a read_timeout, or should we set them to separate values? The documentation doesn't really say anything about best practices using these functions.

[seanmonstar]

In the read_timeout case, a read is close to an IO read operation. (Conceptually, since it's fuzzier with h2). In X amount of time, has the remote sent some data to indicate progress is still being made? It starts with receiving the headers, and then after that it is reset every time some amount of body is received.

It isn't a "total" timeout (reqwest unfortunately just calls that timeout()), or a certain amount of throughput. Just "any bytes" in X time.