Extension cannot connect on first try when loaded automatically

Context

osquery 4.2
Windows 10 Pro 64bit

Test extension

package main

import (
	"context"
	"flag"
	"log"

	"github.com/kolide/osquery-go"
	"github.com/kolide/osquery-go/plugin/table"
)

func main() {
	flSocket := flag.String("socket", "", "")
	flag.Int("timeout", 0, "")
	flag.Int("interval", 0, "")
	flag.Bool("verbose", false, "")
	flag.Parse()

	if *flSocket == "" {
		log.Fatalln("--socket flag cannot be empty")
	}

	server, err := osquery.NewExtensionManagerServer("dev_extension", *flSocket)
	if err != nil {
		log.Fatalf("Error creating osquery extension server: %s\n", err)
	}

	server.RegisterPlugin(
		table.NewPlugin(
			"test_table",
			[]table.ColumnDefinition{
				table.TextColumn("foo"),
			},
			func(ctx context.Context, queryContext table.QueryContext) ([]map[string]string, error) {
				return []map[string]string{
					map[string]string{
						"foo": "bar",
					},
				}, nil
			},
		),
	)

	if err := server.Run(); err != nil {
		log.Fatal(err)
	}
}

Running the above test extension with .\osqueryi.exe --allow_unsafe --extension=.\extension.exe will throw an error registering extension: i/o timeout. Then about a minute later the extension will connect successfully.
Adding a time.Sleep(1 * time.Second) to the beginning of the extension will make it connect on the first try instead.
Similar behavior happens when the extension is run via the extensions.load file.

Reproduce the failure with osqueryi.exe --allow_unsafe --extension=.\extension.exe and the provided Go test extension, then compare startup with and without the one-second sleep. Check the extension manager setup and server.Run entry point, and also test loading through the extensions.load file; done means the extension connects successfully on the first attempt in both cases.