docs: sessionactor

docs/modules/imlight/sessionactor.md

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+# Session Actor
+The `SessionActor` is the [actor](./index.md#actor-model) representation of a connected socket to Imlight. It's supervisor is the server itself.
+
+## Socket Actions
+The `SessionActor`'s primary responsibility is to manage the socket connection it has with it's respective game client. It both receives and sends data to the socket.
+
+When data is received, it is deserialized by the `MessageSerializer` as a potential [magic packet](../internals/systems/kinp/packet-framing.md). Once a magic packet is decoded, it is dispatched to a message handler found in any of the message [services](./messageservice.md).
+
+To send data to the socket, one may use the `SendToSocket()` method found within the `SessionActor`.
+
+## Message Services
+The `SessionActor` has a number of child message [service](./messageservice.md) actors. This means that each `MessageService` is supervised by the `SessionActor`.
+
+Because `SessionActor` is unique and dynamic to each connection, every player has a different set of message services and dispatcher. This is what allows Imlight to compute received packets concurrently.
+
+If an exception is thrown from any of the services, the `SessionActor` will break off and drop the connection it has.
+
+Since the `SessionActor` is the supervisor for these services, there are methods in-place for one `MessageService` to speak to another:
+* `HandleInternalTell()` -- Fire-and-forget.
+* `HandleInternalAsk()` -- Awaits a reply with a timeout of 20 seconds.
+
+There is also an `AskServer()` method, which awaits a reply from the server it is connected to.
+
+::: tip
+The `SessionActor` will only dispatch `IMessage` if it received from the socket. 
+:::
+
+## Gathering Services
+When a `SessionActor` connection is first established, a minimal amount of message [services](./messageservice.md) are granted to the session as per the writing in a [service factory](./servicefactory.md). This means that each `SessionActor` has two different sets of services: one before the session [handshake](../internals/systems/kinp/session.md) is made, and one after.
+
+Each server has its own derived `ServiceFactory` that dictates both set of services.