Future<SecureSocket> connect(host, int port, { SecurityContext context, bool onBadCertificate(X509Certificate certificate), List<String> supportedProtocols })

Constructs a new secure client socket and connects it to the given host on port port. The returned Future will complete with a SecureSocket that is connected and ready for subscription.

The certificate provided by the server is checked using the trusted certificates set in the SecurityContext object. The default SecurityContext object contains a built-in set of trusted root certificates for well-known certificate authorities.

onBadCertificate is an optional handler for unverifiable certificates. The handler receives the X509Certificate, and can inspect it and decide (or let the user decide) whether to accept the connection or not. The handler should return true to continue the SecureSocket connection.

supportedProtocols is an optional list of protocols (in decreasing order of preference) to use during the ALPN protocol negogiation with the server. Example values are "http/1.1" or "h2". The selected protocol can be obtained via SecureSocket.selectedProtocol.

Source 

static Future<SecureSocket> connect(host, int port,
    {SecurityContext context,
    bool onBadCertificate(X509Certificate certificate),
    List<String> supportedProtocols}) {
  return RawSecureSocket
      .connect(host, port,
          context: context,
          onBadCertificate: onBadCertificate,
          supportedProtocols: supportedProtocols)
      .then((rawSocket) => new SecureSocket._(rawSocket));
}