Send data to channel {id}. For a job, it writes it to the stdin of the process. For the stdio channel |channel-stdio|, it writes to Nvim's stdout. Returns the number of bytes written if the write succeeded, 0 otherwise. See |channel-bytes| for more information. {data} may be a string, string convertible, or a list. If {data} is a list, the items will be joined by newlines; any newlines in an item will be sent as NUL. To send a final newline, include a final empty string. Example: :call chansend(id, ["abc", "123\n456", ""]) will send "abc123456". chansend() writes raw data, not RPC messages. If the channel was created with "rpc":v:true then the channel expects RPC messages, use |rpcnotify()| and |rpcrequest()| instead.