things are running quite smoothly!!!compare-to-this

coder@08714a4174bb:~$ nats bench sub foo -s localhost:4223
03:28:04 Starting Core NATS subscriber benchmark [clients=1, msg-size=128 B, msgs=100,000, multi-subject=false, subject=foo]
03:28:04 [1] Starting Core NATS subscriber, expecting 100,000 messages
Finished      6s [====================================================================================] 100%

NATS Core NATS subscriber stats: 14,691 msgs/sec ~ 1.8 MiB/sec ~ 68.06us

1 files changed, 21 insertions, 7 deletions

diff --git a/src/server/main.zig b/src/server/main.zig
index 7328258..a78bab2 100644
--- a/src/server/main.zig
+++ b/src/server/main.zig
@@ -13,6 +13,8 @@ const Subscription = struct {
 
 info: ServerInfo,
 clients: std.AutoHashMapUnmanaged(usize, *ClientState) = .empty,
+
+subs_lock: std.Thread.Mutex = .{},
 subscriptions: std.ArrayList(Subscription) = .empty,
 
 var keep_running = std.atomic.Value(bool).init(true);
@@ -70,10 +72,18 @@ fn addClient(server: *Server, allocator: std.mem.Allocator, id: usize, client: *
 }
 
 fn removeClient(server: *Server, allocator: std.mem.Allocator, id: usize) void {
-    // TODO: implement
-    _ = server;
-    _ = allocator;
-    _ = id;
+    server.subs_lock.lock();
+    defer server.subs_lock.unlock();
+    _ = server.clients.remove(id);
+    const len = server.subscriptions.items.len;
+    for (0..len) |i| {
+        const sub = server.subscriptions.items[len - i - 1];
+        if (sub.client_id == id) {
+            allocator.free(sub.sid);
+            allocator.free(sub.subject);
+            _ = server.subscriptions.swapRemove(i);
+        }
+    }
 }
 
 fn handleConnection(
@@ -109,8 +119,8 @@ fn handleConnection(
     try client_state.start(io);
     defer client_state.deinit(io, allocator);
 
-    try server.addClient(allocator, id, &client_state);
-    defer server.removeClient(allocator, id);
+    try server.addClient(server_allocator, id, &client_state);
+    defer server.removeClient(server_allocator, id);
 
     var msg_arena: std.heap.ArenaAllocator = .init(allocator);
     defer msg_arena.deinit();
@@ -194,6 +204,8 @@ fn publishMessage(server: *Server, io: std.Io, msg: Message.Pub) !void {
 
 fn subscribe(server: *Server, gpa: std.mem.Allocator, id: usize, msg: Message.Sub) !void {
     std.debug.print("Recieved SUBSCRIBE message: {any}\n\n", .{msg});
+    server.subs_lock.lock();
+    defer server.subs_lock.unlock();
     try server.subscriptions.append(gpa, .{
         .subject = try gpa.dupe(u8, msg.subject),
         .client_id = id,
@@ -202,9 +214,11 @@ fn subscribe(server: *Server, gpa: std.mem.Allocator, id: usize, msg: Message.Su
 }
 
 fn unsubscribe(server: *Server, gpa: std.mem.Allocator, id: usize, msg: Message.Unsub) !void {
+    server.subs_lock.lock();
+    defer server.subs_lock.unlock();
     const len = server.subscriptions.items.len;
     for (0..len) |i| {
-        const sub = server.subscriptions.items[len - i];
+        const sub = server.subscriptions.items[len - i - 1];
         if (sub.client_id == id and std.mem.eql(u8, sub.sid, msg.sid)) {
             gpa.free(sub.sid);
             gpa.free(sub.subject);