feat: Introduce Hybrid Logical Clocks in protobuf, update architecture documentation, and add HLC test cases.

lattice-store/src/store.rs

@@ -0,0 +1,35 @@
+//! The main KV store
+
+use std::collections::HashMap;
+
+/// A log-based Key-Value store.
+///
+/// The store is a dynamic "view" generated by replaying entries.
+pub struct Store {
+    data: HashMap<Vec<u8>, Vec<u8>>,
+}
+
+impl Store {
+    /// Create a new empty store.
+    pub fn new() -> Self {
+        Self {
+            data: HashMap::new(),
+        }
+    }
+
+    /// Get a value by key.
+    pub fn get(&self, key: &[u8]) -> Option<&[u8]> {
+        self.data.get(key).map(|v| v.as_slice())
+    }
+
+    /// Set a value (this would normally go through the log).
+    pub fn set(&mut self, key: Vec<u8>, value: Vec<u8>) {
+        self.data.insert(key, value);
+    }
+}
+
+impl Default for Store {
+    fn default() -> Self {
+        Self::new()
+    }
+}