diff --git a/gateway/commands.go b/gateway/commands.go
index 5b30f3b..0f0a429 100644
--- a/gateway/commands.go
+++ b/gateway/commands.go
@@ -101,9 +101,12 @@ func (g *Gateway) UpdateStatus(data UpdateStatusData) error {
 
 // Undocumented
 type GuildSubscribeData struct {
-	GuildID    discord.Snowflake `json:"guild_id"`
 	Typing     bool              `json:"typing"`
 	Activities bool              `json:"activities"`
+	GuildID    discord.Snowflake `json:"guild_id"`
+
+	// Channels is not documented. It's used to fetch the right members sidebar.
+	Channels map[discord.Snowflake][][2]int `json:"channels"`
 }
 
 func (g *Gateway) GuildSubscribe(data GuildSubscribeData) error {
diff --git a/gateway/events.go b/gateway/events.go
index ef73f97..092f0eb 100644
--- a/gateway/events.go
+++ b/gateway/events.go
@@ -106,6 +106,51 @@ type (
 		Presences []discord.Presence `json:"presences,omitempty"`
 	}
 
+	// GuildMemberListUpdate is an undocumented event. It's received when the
+	// client sends over GuildSubscriptions with the Channels field used.
+	// The State package does not handle this event.
+	GuildMemberListUpdate struct {
+		ID          string            `json:"id"`
+		GuildID     discord.Snowflake `json:"guild_id"`
+		MemberCount uint64            `json:"member_count"`
+		OnlineCount uint64            `json:"online_count"`
+
+		// Groups is all the visible role sections.
+		Groups []GuildMemberListGroup `json:"groups"`
+
+		Ops []GuildMemberListOp `json:"ops"`
+	}
+	GuildMemberListGroup struct {
+		ID    string `json:"id"` // either discord.Snowflake Role IDs or "online"
+		Count uint64 `json:"count"`
+	}
+	GuildMemberListOp struct {
+		// Mysterious string, so far spotted to be [SYNC, INSERT, UPDATE, DELETE].
+		Op string `json:"op"`
+
+		// NON-SYNC ONLY
+		// Only available for Ops that aren't "SYNC".
+		Index int                   `json:"index,omitempty"`
+		Item  GuildMemberListOpItem `json:"item,omitempty"`
+
+		// SYNC ONLY
+		// Range requested in GuildSubscribeData.
+		Range [2]int `json:"range,omitempty"`
+		// Items is basically a linear list of roles and members, similarly to
+		// how the client renders it. No, it's not nested.
+		Items []GuildMemberListOpItem `json:"items,omitempty"`
+	}
+	// GuildMemberListOpItem is an enum. Either of the fields are provided, but
+	// never both. Refer to (*GuildMemberListUpdate).Ops for more.
+	GuildMemberListOpItem struct {
+		Group  *GuildMemberListGroup `json:"group,omitempty"`
+		Member *struct {
+			discord.Member
+			HoistedRole string           `json:"hoisted_role"`
+			Presence    discord.Presence `json:"presence"`
+		} `json:"member,omitempty"`
+	}
+
 	GuildRoleCreateEvent struct {
 		GuildID discord.Snowflake `json:"guild_id"`
 		Role    discord.Role      `json:"role"`
diff --git a/gateway/events_map.go b/gateway/events_map.go
index 3580096..ea0286d 100644
--- a/gateway/events_map.go
+++ b/gateway/events_map.go
@@ -34,6 +34,10 @@ var EventCreator = map[string]func() Event{
 	"GUILD_MEMBER_UPDATE": func() Event { return new(GuildMemberUpdateEvent) },
 	"GUILD_MEMBERS_CHUNK": func() Event { return new(GuildMembersChunkEvent) },
 
+	"GUILD_MEMBER_LIST_UPDATE": func() Event {
+		return new(GuildMemberListUpdate)
+	},
+
 	"GUILD_ROLE_CREATE": func() Event { return new(GuildRoleCreateEvent) },
 	"GUILD_ROLE_UPDATE": func() Event { return new(GuildRoleUpdateEvent) },
 	"GUILD_ROLE_DELETE": func() Event { return new(GuildRoleDeleteEvent) },
diff --git a/gateway/gateway.go b/gateway/gateway.go
index f0a4f6f..f64dcc9 100644
--- a/gateway/gateway.go
+++ b/gateway/gateway.go
@@ -27,6 +27,7 @@ const (
 
 	Version  = "6"
 	Encoding = "json"
+	// Compress = "zlib-stream"
 )
 
 var (
@@ -135,6 +136,7 @@ func NewGatewayWithDriver(token string, driver json.Driver) (*Gateway, error) {
 	param := url.Values{}
 	param.Set("v", Version)
 	param.Set("encoding", Encoding)
+	// param.Set("compress", Compress)
 	// Append the form to the URL
 	URL += "?" + param.Encode()
 
@@ -249,15 +251,15 @@ func (g *Gateway) start() error {
 	// This is where we'll get our events
 	ch := g.WS.Listen()
 
+	// Make a new WaitGroup for use in background loops:
+	g.waitGroup = new(sync.WaitGroup)
+
 	// Wait for an OP 10 Hello
 	var hello HelloEvent
 	if _, err := AssertEvent(g, <-ch, HelloOP, &hello); err != nil {
 		return errors.Wrap(err, "Error at Hello")
 	}
 
-	// Make a new WaitGroup for use in background loops:
-	g.waitGroup = new(sync.WaitGroup)
-
 	// Send Discord either the Identify packet (if it's a fresh connection), or
 	// a Resume packet (if it's a dead connection).
 	if g.SessionID == "" {
@@ -375,8 +377,9 @@ func (g *Gateway) send(lock bool, code OPCode, v interface{}) error {
 		return errors.Wrap(err, "Failed to encode payload")
 	}
 
-	ctx, cancel := context.WithTimeout(context.Background(), g.WSTimeout)
-	defer cancel()
+	// ctx, cancel := context.WithTimeout(context.Background(), g.WSTimeout)
+	// defer cancel()
+	ctx := context.Background()
 
 	if lock {
 		g.available.RLock()
diff --git a/gateway/op.go b/gateway/op.go
index 8d08480..563bfc1 100644
--- a/gateway/op.go
+++ b/gateway/op.go
@@ -13,21 +13,20 @@ import (
 type OPCode uint8
 
 const (
-	DispatchOP            OPCode = iota // recv
-	HeartbeatOP                         // send/recv
-	IdentifyOP                          // send...
-	StatusUpdateOP                      //
-	VoiceStateUpdateOP                  //
-	VoiceServerPingOP                   //
-	ResumeOP                            //
-	ReconnectOP                         // recv
-	RequestGuildMembersOP               // send
-	InvalidSessionOP                    // recv...
-	HelloOP
-	HeartbeatAckOP
-	_
-	CallConnectOP
-	GuildSubscriptionsOP
+	DispatchOP            OPCode = 0 // recv
+	HeartbeatOP           OPCode = 1 // send/recv
+	IdentifyOP            OPCode = 2 // send...
+	StatusUpdateOP        OPCode = 3 //
+	VoiceStateUpdateOP    OPCode = 4 //
+	VoiceServerPingOP     OPCode = 5 //
+	ResumeOP              OPCode = 6 //
+	ReconnectOP           OPCode = 7 // recv
+	RequestGuildMembersOP OPCode = 8 // send
+	InvalidSessionOP      OPCode = 9 // recv...
+	HelloOP               OPCode = 10
+	HeartbeatAckOP        OPCode = 11
+	CallConnectOP         OPCode = 13
+	GuildSubscriptionsOP  OPCode = 14
 )
 
 type OP struct {