libcurl requires a minimum of 1 byte per elapsed second

With a certain configuration (low speed options) libcurl requires a minimum of 1 byte for each elapsed second until it timeouts the connection. Sinapse thus sends many comments at a regular interval to avoid this problem. Actually it's sending much more bytes to avoid high latency issues.

This feature isn't enabled by default and requires the `SINAPSE_LIBCURL` environment variable to be set.

I only recommend it for faster development purposes, because it affects all connections and it's a libcurl limitation. You are advised to either not use libcurl, or to disable the low speed limits, and roll your own watcher that checks that a at least one comment was received for a given interval.