Fix concurrency on the client (#183)

* reworked peer connection establishment logic eliminating race conditions and deadlocks while running many peers

client/internal/proxy/proxy.go

@@ -0,0 +1,24 @@
+package proxy
+
+import (
+	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
+	"io"
+	"net"
+	"time"
+)
+
+const DefaultWgKeepAlive = 25 * time.Second
+
+type Config struct {
+	WgListenAddr string
+	RemoteKey    string
+	WgInterface  string
+	AllowedIps   string
+	PreSharedKey *wgtypes.Key
+}
+
+type Proxy interface {
+	io.Closer
+	// Start creates a local remoteConn and starts proxying data from/to remoteConn
+	Start(remoteConn net.Conn) error
+}