Add mutex locking to SetTLSConfig

This change ensures that the SetTLSConfig method is thread-safe by adding a mutex lock. The lock is acquired before any changes to the TLS configuration and released afterward to prevent concurrent access issues.

client.go

@@ -555,6 +555,9 @@ func (c *Client) SetLogger(logger log.Logger) {
 
 // SetTLSConfig overrides the current *tls.Config with the given *tls.Config value
 func (c *Client) SetTLSConfig(tlsconfig *tls.Config) error {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
 	if tlsconfig == nil {
 		return ErrInvalidTLSConfig
 	}