It used to call `enet_host_service` until all events were consumed, but
that also meant constantly polling the connection leading to potentially
unbounded processing time.
It now only service the connection once, and instead consumes all the
retrieved events via `enet_host_check_events`.
It used to always send them reliably when transfer mode was unreliable
or ordered if the packet size was more then the enet host MTU (1400
bytes by default).
This commit also adds a warning when debug is enabled to explain the
effects of sending fragmented packets unreliably.
Move multiplayer classes to "core/multiplayer" subdir.
Move the RPCConfig and enums (TransferMode, RPCMode) to a separate
file (multiplayer.h), and bind them to the global namespace.
Move the RPC handling code to its own class (RPCManager).
Renames "get_rpc_sender_id" to "get_remote_sender_id".
Used by ENetMultiplayerPeer and WebSocketServer to generate network IDs,
and exposed to the user for p2p networks (e.g. WebRTCMultiplayerPeer)
and custom MultiplayerPeer implementations.
* Added a new macro SNAME() that constructs and caches a local stringname.
* Subsequent usages use the cached version.
* Since these use a global static variable, a second refcounter of static usages need to be kept for cleanup time.
* Replaced all theme usages by this new macro.
* Replace all signal emission usages by this new macro.
* Replace all call_deferred usages by this new macro.
This is part of ongoing work to optimize GUI and the editor.
