:sig
function flush_output() bool

:content
`flush_output()` sends the primary output buffer to the host and clears the buffer.
It returns `true` when the host accepts the bytes.
It returns `false` for a WebSocket handler because WebSocket output uses `ws_send()` and `ws_close()`.
An empty buffer returns `true` and remains empty.
Output after the call keeps its order after the flushed bytes.

:example capy render
print("first\n")
flush_output()
print("second\n")

:see-group
output

:see
>print
>ws_send
