code: func (ctx *RequestCtx) TLSConnectionState() *tls.ConnectionState {
  	tlsConn, ok := ctx.c.(connTLSer)
  	if !ok {
  		return nil
  	}
  	state := tlsConn.ConnectionState()
  	return &state
  }
docs: // TLSConnectionState returns TLS connection state.
  //
  // The function returns nil if the underlying connection isn't tls.Conn.
  //
  // The returned state may be used for verifying TLS version, client certificates,
  // etc.