add module docs for connection and manager

solar/src/actors/network/connection.rs

@@ -1,3 +1,10 @@
+//! Handle inbound and outbound TCP connections.
+//!
+//! Inbound connections originate in the TCP server module, while outbound
+//! connection attempts are intiated by the connection scheduler module.
+//!
+//! Connection events are emitted and handled by the connection manager.
+
 use std::fmt::Display;
 
 use async_std::net::TcpStream;

solar/src/actors/network/connection_manager.rs

@@ -1,3 +1,14 @@
+//! Event-driven connection manager.
+//!
+//! The connection manager serves to register new TCP connections and handle
+//! each connection as it passes through several phases (eg. connection
+//! establishment, handshake, replication etc.).
+//!
+//! An event loop listens for connection events and executes handlers for each.
+//!
+//! Connection data, including the underlying TCP stream, is passed around with
+//! each event variant - allowing the handlers to take ownership of the data.
+
 use std::{collections::HashSet, net::Shutdown};
 
 use async_std::{