Response:
Array
(
    [headers] => Requests_Utility_CaseInsensitiveDictionary Object
        (
            [data:protected] => Array
                (
                    [date] => Mon, 13 Jul 2020 20:44:17 GMT
                    [content-type] => application/json; charset=utf-8
                    [set-cookie] => __cfduid=d0dabaed9682794e098b542b7f72d53081594673057; expires=Wed, 12-Aug-20 20:44:17 GMT; path=/; domain=.pushover.net; HttpOnly; SameSite=Lax
                    [x-frame-options] => Array
                        (
                            [0] => SAMEORIGIN
                            [1] => DENY
                        )

                    [x-xss-protection] => 1; mode=block
                    [x-content-type-options] => nosniff
                    [x-download-options] => noopen
                    [x-permitted-cross-domain-policies] => none
                    [referrer-policy] => strict-origin-when-cross-origin
                    [access-control-allow-origin] => *
                    [access-control-allow-methods] => POST, OPTIONS
                    [access-control-allow-headers] => X-Requested-With, X-Prototype-Version, Origin, Accept, Content-Type, X-CSRF-Token, X-Pushover-App, Authorization
                    [access-control-max-age] => 1728000
                    [x-limit-app-limit] => 7500
                    [x-limit-app-remaining] => 7500
                    [x-limit-app-reset] => 1596258000
                    [etag] => W/"e87935a2f5141eb1d90de4090a8853ef"
                    [cache-control] => max-age=0, private, must-revalidate
                    [x-request-id] => 838c9ebf-2877-4237-9446-bdffc738f88f
                    [x-runtime] => 0.013574
                    [strict-transport-security] => max-age=31536000
                    [cf-cache-status] => DYNAMIC
                    [cf-request-id] => 03eb84e5620000ccfaa9855200000001
                    [expect-ct] => max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"
                    [server] => cloudflare
                    [cf-ray] => 5b25d74f0eecccfa-EWR
                    [content-encoding] => gzip
                )

        )

    [body] => {"info":"no active devices to send to","status":1,"request":"838c9ebf-2877-4237-9446-bdffc738f88f"}
    [response] => Array
        (
            [code] => 200
            [message] => OK
        )

    [cookies] => Array
        (
            [0] => WP_Http_Cookie Object
                (
                    [name] => __cfduid
                    [value] => d0dabaed9682794e098b542b7f72d53081594673057
                    [expires] => 1597265057
                    [path] => /
                    [domain] => pushover.net
                )

        )

    [filename] => 
    [http_response] => WP_HTTP_Requests_Response Object
        (
            [response:protected] => Requests_Response Object
                (
                    [body] => {"info":"no active devices to send to","status":1,"request":"838c9ebf-2877-4237-9446-bdffc738f88f"}
                    [raw] => HTTP/1.1 200 OK
Date: Mon, 13 Jul 2020 20:44:17 GMT
Content-Type: application/json; charset=utf-8
Transfer-Encoding: chunked
Connection: close
Set-Cookie: __cfduid=d0dabaed9682794e098b542b7f72d53081594673057; expires=Wed, 12-Aug-20 20:44:17 GMT; path=/; domain=.pushover.net; HttpOnly; SameSite=Lax
X-Frame-Options: SAMEORIGIN
X-XSS-Protection: 1; mode=block
X-Content-Type-Options: nosniff
X-Download-Options: noopen
X-Permitted-Cross-Domain-Policies: none
Referrer-Policy: strict-origin-when-cross-origin
Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: POST, OPTIONS
Access-Control-Allow-Headers: X-Requested-With, X-Prototype-Version, Origin, Accept, Content-Type, X-CSRF-Token, X-Pushover-App, Authorization
Access-Control-Max-Age: 1728000
X-Limit-App-Limit: 7500
X-Limit-App-Remaining: 7500
X-Limit-App-Reset: 1596258000
ETag: W/"e87935a2f5141eb1d90de4090a8853ef"
Cache-Control: max-age=0, private, must-revalidate
X-Request-Id: 838c9ebf-2877-4237-9446-bdffc738f88f
X-Runtime: 0.013574
X-Frame-Options: DENY
Strict-Transport-Security: max-age=31536000
CF-Cache-Status: DYNAMIC
cf-request-id: 03eb84e5620000ccfaa9855200000001
Expect-CT: max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"
Server: cloudflare
CF-RAY: 5b25d74f0eecccfa-EWR
Content-Encoding: gzip

{"info":"no active devices to send to","status":1,"request":"838c9ebf-2877-4237-9446-bdffc738f88f"}
                    [headers] => Requests_Response_Headers Object
                        (
                            [data:protected] => Array
                                (
                                    [date] => Array
                                        (
                                            [0] => Mon, 13 Jul 2020 20:44:17 GMT
                                        )

                                    [content-type] => Array
                                        (
                                            [0] => application/json; charset=utf-8
                                        )

                                    [set-cookie] => Array
                                        (
                                            [0] => __cfduid=d0dabaed9682794e098b542b7f72d53081594673057; expires=Wed, 12-Aug-20 20:44:17 GMT; path=/; domain=.pushover.net; HttpOnly; SameSite=Lax
                                        )

                                    [x-frame-options] => Array
                                        (
                                            [0] => SAMEORIGIN
                                            [1] => DENY
                                        )

                                    [x-xss-protection] => Array
                                        (
                                            [0] => 1; mode=block
                                        )

                                    [x-content-type-options] => Array
                                        (
                                            [0] => nosniff
                                        )

                                    [x-download-options] => Array
                                        (
                                            [0] => noopen
                                        )

                                    [x-permitted-cross-domain-policies] => Array
                                        (
                                            [0] => none
                                        )

                                    [referrer-policy] => Array
                                        (
                                            [0] => strict-origin-when-cross-origin
                                        )

                                    [access-control-allow-origin] => Array
                                        (
                                            [0] => *
                                        )

                                    [access-control-allow-methods] => Array
                                        (
                                            [0] => POST, OPTIONS
                                        )

                                    [access-control-allow-headers] => Array
                                        (
                                            [0] => X-Requested-With, X-Prototype-Version, Origin, Accept, Content-Type, X-CSRF-Token, X-Pushover-App, Authorization
                                        )

                                    [access-control-max-age] => Array
                                        (
                                            [0] => 1728000
                                        )

                                    [x-limit-app-limit] => Array
                                        (
                                            [0] => 7500
                                        )

                                    [x-limit-app-remaining] => Array
                                        (
                                            [0] => 7500
                                        )

                                    [x-limit-app-reset] => Array
                                        (
                                            [0] => 1596258000
                                        )

                                    [etag] => Array
                                        (
                                            [0] => W/"e87935a2f5141eb1d90de4090a8853ef"
                                        )

                                    [cache-control] => Array
                                        (
                                            [0] => max-age=0, private, must-revalidate
                                        )

                                    [x-request-id] => Array
                                        (
                                            [0] => 838c9ebf-2877-4237-9446-bdffc738f88f
                                        )

                                    [x-runtime] => Array
                                        (
                                            [0] => 0.013574
                                        )

                                    [strict-transport-security] => Array
                                        (
                                            [0] => max-age=31536000
                                        )

                                    [cf-cache-status] => Array
                                        (
                                            [0] => DYNAMIC
                                        )

                                    [cf-request-id] => Array
                                        (
                                            [0] => 03eb84e5620000ccfaa9855200000001
                                        )

                                    [expect-ct] => Array
                                        (
                                            [0] => max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"
                                        )

                                    [server] => Array
                                        (
                                            [0] => cloudflare
                                        )

                                    [cf-ray] => Array
                                        (
                                            [0] => 5b25d74f0eecccfa-EWR
                                        )

                                    [content-encoding] => Array
                                        (
                                            [0] => gzip
                                        )

                                )

                        )

                    [status_code] => 200
                    [protocol_version] => 1.1
                    [success] => 1
                    [redirects] => 0
                    [url] => https://api.pushover.net/1/messages.json
                    [history] => Array
                        (
                        )

                    [cookies] => Requests_Cookie_Jar Object
                        (
                            [cookies:protected] => Array
                                (
                                    [__cfduid] => Requests_Cookie Object
                                        (
                                            [name] => __cfduid
                                            [value] => d0dabaed9682794e098b542b7f72d53081594673057
                                            [attributes] => Requests_Utility_CaseInsensitiveDictionary Object
                                                (
                                                    [data:protected] => Array
                                                        (
                                                            [expires] => 1597265057
                                                            [path] => /
                                                            [domain] => pushover.net
                                                            [httponly] => 1
                                                            [samesite] => Lax
                                                        )

                                                )

                                            [flags] => Array
                                                (
                                                    [creation] => 1594673057
                                                    [last-access] => 1594673057
                                                    [persistent] => 
                                                    [host-only] => 
                                                )

                                            [reference_time] => 1594673057
                                        )

                                )

                        )

                )

            [filename:protected] => 
            [data] => 
            [headers] => 
            [status] => 
        )

)