Caddy (and probably other webservers) add a Content-Type header
when one was not supplied by the application backend. Under Chromium,
the css file is not interpreted if the webserver delivers it with
Content-Type: text/plain, althugh it does work if no Content-Type
header is set. To prevent the frontend proxy from adding the wrong
header, set it correctly in the first place
Read or writes to bad file descriptors threw exceptions, just log
this instead. Also make sure that LaminarClients are removed from
the list of clients when a connection is aggressively dropped, and
add test
Now explicitly closed connections on the client side are
closed with a clean error code. This is motivated by upcoming
work to detect broken websockets and automatically reconnect
reading into a static buffer is a race condition that is only
manifested under load. There's no guarantee the clause in then()
will run before another task overwrites the buffer. Allocating
a local string is the only correct solution
Improve the boundary between RpcImpl and LaminarInterface such
that the Laminar class doesn't require any types from kj/async.h.
The necessary logic moved from Laminar to RpcImpl and the notification
now happens by abstract virtual callback instead of kj::Promise.
Also remove the fairly useless 'wait' RPC call and drop the wrappers
around kj::PromiseFulfillerPair
