diff --git a/vendor/github.com/mongodb/mongo-go-driver/x/mongo/driver/find.go b/vendor/github.com/mongodb/mongo-go-driver/x/mongo/driver/find.go
new file mode 100644
index 0000000..0287ca7
--- /dev/null
+++ b/vendor/github.com/mongodb/mongo-go-driver/x/mongo/driver/find.go
@@ -0,0 +1,517 @@
+// Copyright (C) MongoDB, Inc. 2017-present.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+
+package driver
+
+import (
+	"context"
+
+	"time"
+
+	"errors"
+
+	"github.com/mongodb/mongo-go-driver/bson/bsoncodec"
+	"github.com/mongodb/mongo-go-driver/mongo/options"
+	"github.com/mongodb/mongo-go-driver/mongo/readpref"
+	"github.com/mongodb/mongo-go-driver/x/bsonx"
+	"github.com/mongodb/mongo-go-driver/x/bsonx/bsoncore"
+	"github.com/mongodb/mongo-go-driver/x/mongo/driver/session"
+	"github.com/mongodb/mongo-go-driver/x/mongo/driver/topology"
+	"github.com/mongodb/mongo-go-driver/x/mongo/driver/uuid"
+	"github.com/mongodb/mongo-go-driver/x/network/command"
+	"github.com/mongodb/mongo-go-driver/x/network/connection"
+	"github.com/mongodb/mongo-go-driver/x/network/description"
+	"github.com/mongodb/mongo-go-driver/x/network/wiremessage"
+)
+
+// Find handles the full cycle dispatch and execution of a find command against the provided
+// topology.
+func Find(
+	ctx context.Context,
+	cmd command.Find,
+	topo *topology.Topology,
+	selector description.ServerSelector,
+	clientID uuid.UUID,
+	pool *session.Pool,
+	registry *bsoncodec.Registry,
+	opts ...*options.FindOptions,
+) (*BatchCursor, error) {
+
+	ss, err := topo.SelectServer(ctx, selector)
+	if err != nil {
+		return nil, err
+	}
+
+	desc := ss.Description()
+	conn, err := ss.Connection(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer conn.Close()
+
+	if desc.WireVersion.Max < 4 {
+		return legacyFind(ctx, cmd, registry, ss, conn, opts...)
+	}
+
+	rp, err := getReadPrefBasedOnTransaction(cmd.ReadPref, cmd.Session)
+	if err != nil {
+		return nil, err
+	}
+	cmd.ReadPref = rp
+
+	// If no explicit session and deployment supports sessions, start implicit session.
+	if cmd.Session == nil && topo.SupportsSessions() {
+		cmd.Session, err = session.NewClientSession(pool, clientID, session.Implicit)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	fo := options.MergeFindOptions(opts...)
+	if fo.AllowPartialResults != nil {
+		cmd.Opts = append(cmd.Opts, bsonx.Elem{"allowPartialResults", bsonx.Boolean(*fo.AllowPartialResults)})
+	}
+	if fo.BatchSize != nil {
+		elem := bsonx.Elem{"batchSize", bsonx.Int32(*fo.BatchSize)}
+		cmd.Opts = append(cmd.Opts, elem)
+		cmd.CursorOpts = append(cmd.CursorOpts, elem)
+
+		if fo.Limit != nil && *fo.BatchSize != 0 && *fo.Limit <= int64(*fo.BatchSize) {
+			cmd.Opts = append(cmd.Opts, bsonx.Elem{"singleBatch", bsonx.Boolean(true)})
+		}
+	}
+	if fo.Collation != nil {
+		if desc.WireVersion.Max < 5 {
+			return nil, ErrCollation
+		}
+		cmd.Opts = append(cmd.Opts, bsonx.Elem{"collation", bsonx.Document(fo.Collation.ToDocument())})
+	}
+	if fo.Comment != nil {
+		cmd.Opts = append(cmd.Opts, bsonx.Elem{"comment", bsonx.String(*fo.Comment)})
+	}
+	if fo.CursorType != nil {
+		switch *fo.CursorType {
+		case options.Tailable:
+			cmd.Opts = append(cmd.Opts, bsonx.Elem{"tailable", bsonx.Boolean(true)})
+		case options.TailableAwait:
+			cmd.Opts = append(cmd.Opts, bsonx.Elem{"tailable", bsonx.Boolean(true)}, bsonx.Elem{"awaitData", bsonx.Boolean(true)})
+		}
+	}
+	if fo.Hint != nil {
+		hintElem, err := interfaceToElement("hint", fo.Hint, registry)
+		if err != nil {
+			return nil, err
+		}
+
+		cmd.Opts = append(cmd.Opts, hintElem)
+	}
+	if fo.Limit != nil {
+		cmd.Opts = append(cmd.Opts, bsonx.Elem{"limit", bsonx.Int64(*fo.Limit)})
+	}
+	if fo.Max != nil {
+		maxElem, err := interfaceToElement("max", fo.Max, registry)
+		if err != nil {
+			return nil, err
+		}
+
+		cmd.Opts = append(cmd.Opts, maxElem)
+	}
+	if fo.MaxAwaitTime != nil {
+		// Specified as maxTimeMS on the in the getMore command and not given in initial find command.
+		cmd.CursorOpts = append(cmd.CursorOpts, bsonx.Elem{"maxTimeMS", bsonx.Int64(int64(*fo.MaxAwaitTime / time.Millisecond))})
+	}
+	if fo.MaxTime != nil {
+		cmd.Opts = append(cmd.Opts, bsonx.Elem{"maxTimeMS", bsonx.Int64(int64(*fo.MaxTime / time.Millisecond))})
+	}
+	if fo.Min != nil {
+		minElem, err := interfaceToElement("min", fo.Min, registry)
+		if err != nil {
+			return nil, err
+		}
+
+		cmd.Opts = append(cmd.Opts, minElem)
+	}
+	if fo.NoCursorTimeout != nil {
+		cmd.Opts = append(cmd.Opts, bsonx.Elem{"noCursorTimeout", bsonx.Boolean(*fo.NoCursorTimeout)})
+	}
+	if fo.OplogReplay != nil {
+		cmd.Opts = append(cmd.Opts, bsonx.Elem{"oplogReplay", bsonx.Boolean(*fo.OplogReplay)})
+	}
+	if fo.Projection != nil {
+		projElem, err := interfaceToElement("projection", fo.Projection, registry)
+		if err != nil {
+			return nil, err
+		}
+
+		cmd.Opts = append(cmd.Opts, projElem)
+	}
+	if fo.ReturnKey != nil {
+		cmd.Opts = append(cmd.Opts, bsonx.Elem{"returnKey", bsonx.Boolean(*fo.ReturnKey)})
+	}
+	if fo.ShowRecordID != nil {
+		cmd.Opts = append(cmd.Opts, bsonx.Elem{"showRecordId", bsonx.Boolean(*fo.ShowRecordID)})
+	}
+	if fo.Skip != nil {
+		cmd.Opts = append(cmd.Opts, bsonx.Elem{"skip", bsonx.Int64(*fo.Skip)})
+	}
+	if fo.Snapshot != nil {
+		cmd.Opts = append(cmd.Opts, bsonx.Elem{"snapshot", bsonx.Boolean(*fo.Snapshot)})
+	}
+	if fo.Sort != nil {
+		sortElem, err := interfaceToElement("sort", fo.Sort, registry)
+		if err != nil {
+			return nil, err
+		}
+
+		cmd.Opts = append(cmd.Opts, sortElem)
+	}
+
+	res, err := cmd.RoundTrip(ctx, desc, conn)
+	if err != nil {
+		closeImplicitSession(cmd.Session)
+		return nil, err
+	}
+
+	return NewBatchCursor(bsoncore.Document(res), cmd.Session, cmd.Clock, ss.Server, cmd.CursorOpts...)
+}
+
+// legacyFind handles the dispatch and execution of a find operation against a pre-3.2 server.
+func legacyFind(
+	ctx context.Context,
+	cmd command.Find,
+	registry *bsoncodec.Registry,
+	ss *topology.SelectedServer,
+	conn connection.Connection,
+	opts ...*options.FindOptions,
+) (*BatchCursor, error) {
+	query := wiremessage.Query{
+		FullCollectionName: cmd.NS.DB + "." + cmd.NS.Collection,
+	}
+
+	fo := options.MergeFindOptions(opts...)
+	optsDoc, err := createLegacyOptionsDoc(fo, registry)
+	if err != nil {
+		return nil, err
+	}
+	if fo.Projection != nil {
+		projDoc, err := interfaceToDocument(fo.Projection, registry)
+		if err != nil {
+			return nil, err
+		}
+
+		projRaw, err := projDoc.MarshalBSON()
+		if err != nil {
+			return nil, err
+		}
+		query.ReturnFieldsSelector = projRaw
+	}
+	if fo.Skip != nil {
+		query.NumberToSkip = int32(*fo.Skip)
+		query.SkipSet = true
+	}
+	// batch size of 1 not possible with OP_QUERY because the cursor will be closed immediately
+	if fo.BatchSize != nil && *fo.BatchSize == 1 {
+		query.NumberToReturn = 2
+	} else {
+		query.NumberToReturn = calculateNumberToReturn(fo)
+	}
+	query.Flags = calculateLegacyFlags(fo)
+
+	query.BatchSize = fo.BatchSize
+	if fo.Limit != nil {
+		i := int32(*fo.Limit)
+		query.Limit = &i
+	}
+
+	// set read preference and/or slaveOK flag
+	desc := ss.SelectedDescription()
+	if slaveOkNeeded(cmd.ReadPref, desc) {
+		query.Flags |= wiremessage.SlaveOK
+	}
+	optsDoc = addReadPref(cmd.ReadPref, desc.Server.Kind, optsDoc)
+
+	if cmd.Filter == nil {
+		cmd.Filter = bsonx.Doc{}
+	}
+
+	// filter must be wrapped in $query if other $modifiers are used
+	var queryDoc bsonx.Doc
+	if len(optsDoc) == 0 {
+		queryDoc = cmd.Filter
+	} else {
+		filterDoc := bsonx.Doc{
+			{"$query", bsonx.Document(cmd.Filter)},
+		}
+		// $query should go first
+		queryDoc = append(filterDoc, optsDoc...)
+	}
+
+	queryRaw, err := queryDoc.MarshalBSON()
+	if err != nil {
+		return nil, err
+	}
+	query.Query = queryRaw
+
+	reply, err := roundTripQuery(ctx, query, conn)
+	if err != nil {
+		return nil, err
+	}
+
+	var cursorLimit int32
+	var cursorBatchSize int32
+	if query.Limit != nil {
+		cursorLimit = int32(*query.Limit)
+		if cursorLimit < 0 {
+			cursorLimit *= -1
+		}
+	}
+	if query.BatchSize != nil {
+		cursorBatchSize = int32(*query.BatchSize)
+	}
+
+	return NewLegacyBatchCursor(cmd.NS, reply.CursorID, reply.Documents, cursorLimit, cursorBatchSize, ss.Server)
+}
+
+func createLegacyOptionsDoc(fo *options.FindOptions, registry *bsoncodec.Registry) (bsonx.Doc, error) {
+	var optsDoc bsonx.Doc
+
+	if fo.Collation != nil {
+		return nil, ErrCollation
+	}
+	if fo.Comment != nil {
+		optsDoc = append(optsDoc, bsonx.Elem{"$comment", bsonx.String(*fo.Comment)})
+	}
+	if fo.Hint != nil {
+		hintElem, err := interfaceToElement("$hint", fo.Hint, registry)
+		if err != nil {
+			return nil, err
+		}
+
+		optsDoc = append(optsDoc, hintElem)
+	}
+	if fo.Max != nil {
+		maxElem, err := interfaceToElement("$max", fo.Max, registry)
+		if err != nil {
+			return nil, err
+		}
+
+		optsDoc = append(optsDoc, maxElem)
+	}
+	if fo.MaxTime != nil {
+		optsDoc = append(optsDoc, bsonx.Elem{"$maxTimeMS", bsonx.Int64(int64(*fo.MaxTime / time.Millisecond))})
+	}
+	if fo.Min != nil {
+		minElem, err := interfaceToElement("$min", fo.Min, registry)
+		if err != nil {
+			return nil, err
+		}
+
+		optsDoc = append(optsDoc, minElem)
+	}
+	if fo.ReturnKey != nil {
+		optsDoc = append(optsDoc, bsonx.Elem{"$returnKey", bsonx.Boolean(*fo.ReturnKey)})
+	}
+	if fo.ShowRecordID != nil {
+		optsDoc = append(optsDoc, bsonx.Elem{"$showDiskLoc", bsonx.Boolean(*fo.ShowRecordID)})
+	}
+	if fo.Snapshot != nil {
+		optsDoc = append(optsDoc, bsonx.Elem{"$snapshot", bsonx.Boolean(*fo.Snapshot)})
+	}
+	if fo.Sort != nil {
+		sortElem, err := interfaceToElement("$orderby", fo.Sort, registry)
+		if err != nil {
+			return nil, err
+		}
+
+		optsDoc = append(optsDoc, sortElem)
+	}
+
+	return optsDoc, nil
+}
+
+func calculateLegacyFlags(fo *options.FindOptions) wiremessage.QueryFlag {
+	var flags wiremessage.QueryFlag
+
+	if fo.AllowPartialResults != nil {
+		flags |= wiremessage.Partial
+	}
+	if fo.CursorType != nil {
+		switch *fo.CursorType {
+		case options.Tailable:
+			flags |= wiremessage.TailableCursor
+		case options.TailableAwait:
+			flags |= wiremessage.TailableCursor
+			flags |= wiremessage.AwaitData
+		}
+	}
+	if fo.NoCursorTimeout != nil {
+		flags |= wiremessage.NoCursorTimeout
+	}
+	if fo.OplogReplay != nil {
+		flags |= wiremessage.OplogReplay
+	}
+
+	return flags
+}
+
+// calculate the number to return for the first find query
+func calculateNumberToReturn(opts *options.FindOptions) int32 {
+	var numReturn int32
+	var limit int32
+	var batchSize int32
+
+	if opts.Limit != nil {
+		limit = int32(*opts.Limit)
+	}
+	if opts.BatchSize != nil {
+		batchSize = int32(*opts.BatchSize)
+	}
+
+	if limit < 0 {
+		numReturn = limit
+	} else if limit == 0 {
+		numReturn = batchSize
+	} else if limit < batchSize {
+		numReturn = limit
+	} else {
+		numReturn = batchSize
+	}
+
+	return numReturn
+}
+
+func slaveOkNeeded(rp *readpref.ReadPref, desc description.SelectedServer) bool {
+	if desc.Kind == description.Single && desc.Server.Kind != description.Mongos {
+		return true
+	}
+	if rp == nil {
+		// assume primary
+		return false
+	}
+
+	return rp.Mode() != readpref.PrimaryMode
+}
+
+func addReadPref(rp *readpref.ReadPref, kind description.ServerKind, query bsonx.Doc) bsonx.Doc {
+	if !readPrefNeeded(rp, kind) {
+		return query
+	}
+
+	doc := createReadPref(rp)
+	if doc == nil {
+		return query
+	}
+
+	return query.Append("$readPreference", bsonx.Document(doc))
+}
+
+func readPrefNeeded(rp *readpref.ReadPref, kind description.ServerKind) bool {
+	if kind != description.Mongos || rp == nil {
+		return false
+	}
+
+	// simple Primary or SecondaryPreferred is communicated via slaveOk to Mongos.
+	if rp.Mode() == readpref.PrimaryMode || rp.Mode() == readpref.SecondaryPreferredMode {
+		if _, ok := rp.MaxStaleness(); !ok && len(rp.TagSets()) == 0 {
+			return false
+		}
+	}
+
+	return true
+}
+
+func createReadPref(rp *readpref.ReadPref) bsonx.Doc {
+	if rp == nil {
+		return nil
+	}
+
+	doc := bsonx.Doc{}
+
+	switch rp.Mode() {
+	case readpref.PrimaryMode:
+		doc = append(doc, bsonx.Elem{"mode", bsonx.String("primary")})
+	case readpref.PrimaryPreferredMode:
+		doc = append(doc, bsonx.Elem{"mode", bsonx.String("primaryPreferred")})
+	case readpref.SecondaryPreferredMode:
+		doc = append(doc, bsonx.Elem{"mode", bsonx.String("secondaryPreferred")})
+	case readpref.SecondaryMode:
+		doc = append(doc, bsonx.Elem{"mode", bsonx.String("secondary")})
+	case readpref.NearestMode:
+		doc = append(doc, bsonx.Elem{"mode", bsonx.String("nearest")})
+	}
+
+	sets := make([]bsonx.Val, 0, len(rp.TagSets()))
+	for _, ts := range rp.TagSets() {
+		if len(ts) == 0 {
+			continue
+		}
+		set := bsonx.Doc{}
+		for _, t := range ts {
+			set = append(set, bsonx.Elem{t.Name, bsonx.String(t.Value)})
+		}
+		sets = append(sets, bsonx.Document(set))
+	}
+	if len(sets) > 0 {
+		doc = append(doc, bsonx.Elem{"tags", bsonx.Array(sets)})
+	}
+	if d, ok := rp.MaxStaleness(); ok {
+		doc = append(doc, bsonx.Elem{"maxStalenessSeconds", bsonx.Int32(int32(d.Seconds()))})
+	}
+
+	return doc
+}
+
+func roundTripQuery(ctx context.Context, query wiremessage.Query, conn connection.Connection) (wiremessage.Reply, error) {
+	err := conn.WriteWireMessage(ctx, query)
+	if err != nil {
+		if _, ok := err.(command.Error); ok {
+			return wiremessage.Reply{}, err
+		}
+		return wiremessage.Reply{}, command.Error{
+			Message: err.Error(),
+			Labels:  []string{command.NetworkError},
+		}
+	}
+
+	wm, err := conn.ReadWireMessage(ctx)
+	if err != nil {
+		if _, ok := err.(command.Error); ok {
+			return wiremessage.Reply{}, err
+		}
+		// Connection errors are transient
+		return wiremessage.Reply{}, command.Error{
+			Message: err.Error(),
+			Labels:  []string{command.NetworkError},
+		}
+	}
+
+	reply, ok := wm.(wiremessage.Reply)
+	if !ok {
+		return wiremessage.Reply{}, errors.New("did not receive OP_REPLY response")
+	}
+
+	err = validateOpReply(reply)
+	if err != nil {
+		return wiremessage.Reply{}, err
+	}
+
+	return reply, nil
+}
+
+func validateOpReply(reply wiremessage.Reply) error {
+	if int(reply.NumberReturned) != len(reply.Documents) {
+		return command.NewCommandResponseError(command.ReplyDocumentMismatch, nil)
+	}
+
+	if reply.ResponseFlags&wiremessage.QueryFailure == wiremessage.QueryFailure {
+		return command.QueryFailureError{
+			Message:  "query failure",
+			Response: reply.Documents[0],
+		}
+	}
+
+	return nil
+}