Insufficient buffer size causes truncation, malformed request

[InterLinked1]

There are some static buffer sizes in discord-gateway_dispatch.c that can be too small for large requests, causing truncation of the JSON payload and causing the Discord API to disconnect us, aborting any requests in progress. For example, this limit can be hit when requesting guild members with a payload of between 40 and 45 users, with a buffer size of 1024.

This commit partially addresses this with a stopgap fix: b860d9f

Seems like dynamic allocation should be used instead?