Response.ok(body, {Map<String, String> headers, Encoding encoding, Map<String, Object> context})

Constructs a 200 OK response.

This indicates that the request has succeeded.

body is the response body. It may be either a String, a Stream>, or null to indicate no body. If it's a String, encoding is used to encode it to a Stream>. It defaults to UTF-8.

If encoding is passed, the "encoding" field of the Content-Type header in headers will be set appropriately. If there is no existing Content-Type header, it will be set to "application/octet-stream".

Source 

Response.ok(body, {Map<String, String> headers, Encoding encoding,
  Map<String, Object> context})
    : this(200, body: body, headers: headers, encoding: encoding,
        context: context);