ThreadChannel is a thread, or a post of a forum. It is what channel.isThread() gives, and what message.startThread(), channel.startThread() and forum.createPost() return.
How to send, edit and read messages is in Sending messages.
Properties
It also has everything of Channel and what channels with messages share. A thread is not aGuildChannel: it has no overwrites of its own, and takes the permissions of the channel it is in.
The channel the thread was created in;
null when it is of a kind this version does not know.Helpers
permissionsFor()
Reading from Discord
fetchMembers()
ThreadMember.
Discord documentation
Actions
edit()
ThreadEditOptions.
Discord documentation