+# namespace http\Client\Curl
+
+The http\Client\Curl namespace holds option value constants specific to the curl driver of the http\Client.
+
+## Constants:
+
+### HTTP Protocol Version
+
+* HTTP_VERSION_1_0
+ Use HTTP/1.0 protocol version.
+* HTTP_VERSION_1_1
+ Use HTTP/1.1 protocol version.
+* HTTP_VERSION_ANY
+ Use any HTTP protocol version.
+
+### SSL Protocol Version
+
+* SSL_VERSION_TLSv1
+ Use TLSv1 encryption.
+* SSL_VERSION_SSLv2
+ Use SSLv2 encryption.
+* SSL_VERSION_SSLv3
+ Use SSLv3 encryption.
+* SSL_VERSION_ANY
+ Use any encryption.
+
+### DNS IP Version
+
+* IPRESOLVE_V4
+ Use IPv4 resolver.
+* IPRESOLVE_V6
+ Use IPv6 resolver.
+* IPRESOLVE_ANY
+ Use any resolver.
+
+### Authentication Type
+
+* AUTH_BASIC
+ Use Basic authentication.
+* AUTH_DIGEST
+ Use Digest authentication.
+* AUTH_DIGEST_IE
+ Use IE (lower v7) quirks with Digest authentication. Available if libcurl is v7.19.3 or more recent.
+* AUTH_NTLM
+ Use NTLM authentication.
+* AUTH_GSSNEG
+ Use GSS-Negotiate authentication.
+* AUTH_ANY
+ Use any authentication.
+
+### Proxy Protocol Version
+
+* PROXY_SOCKS4
+ Use SOCKSv4 proxy protocol.
+* PROXY_SOCKS4A
+ Use SOCKSv4a proxy protocol.
+* PROXY_SOCKS5_HOSTNAME
+ Use SOCKS5h proxy protocol.
+* PROXY_SOCKS5
+ Use SOCKS5 proxy protoccol.
+* PROXY_HTTP
+ Use HTTP/1.1 proxy protocol.
+* PROXY_HTTP_1_0
+ Use HTTP/1.0 proxy protocol. Available if libcurl is v7.19.4 or more recent.
+
+### POST Redirection Behavior
+
+* POSTREDIR_301
+ Keep POSTing on 301 redirects. Available if libcurl is v7.19.1 or more recent.
+* POSTREDIR_302
+ Keep POSTing on 302 redirects. Available if libcurl is v7.19.1 or more recent.
+* POSTREDIR_ALL
+ Keep POSTing on any redirect. Available if libcurl is v7.19.1 or more recent.
+
+
+## Options:
+
+### HTTP
+
+* int $protocol
+ The HTTP protocol version. See http\Client\Curl::HTTP_VERSION_* constants.
+
+### Proxies
+
+* string $proxyhost
+ The hostname of the proxy.
+* int $proxytype
+ See http\Client\Curl::PROXY_* constants.
+* int $proxyport
+ The port number of the proxy.
+* string $proxyauth
+ user:password
+* int $proxyauthtype
+ See http\Client\Curl::AUTH_* constants.
+* bool $proxytunnel
+ Tunnel all operations through the proxy.
+* string $noproxy
+ Comma separated list of hosts where no proxy should be used. Available if libcurl is v7.19.4 or more recent.
+
+### DNS
+
+* int $dns_cache_timeout
+ Resolved hosts will be kept fot this number of seconds.
+* int $ipresolve
+ See http\Client\Curl::IPRESOLVE_* constants.
+* array $resolve
+ A list of HOST:PORT:ADDRESS mappings which pre-populate the DNS cache. Available if libcurl is v7.21.3 or more recent.
+* string $dns_servers
+ Comma separated list of custom DNS servers of the form HOST[:PORT]. Available if libcurl is v7.24.0 or more recent.
+
+### Limits
+
+* int $low_speed_limit
+ Minimum speed in bytes per second.
+* int $low_speed_time
+ Maximum time in seconds the transfer can be below $low_speed_limit before cancelling.
+* int $maxfilesize
+ Maximum download size.
+
+### Connection handling
+
+* bool $fresh_connect
+ Force a new connection.
+* bool $forbid_reuse
+ Force closing the connection.
+
+### Networking
+
+* string $interface
+ Outgoing interface name.
+* array $portrange
+ A tuple of min/max ports.
+* int $port
+ Override the URL's port.
+* int $address_scope
+ RFC4007 zone_id. Available if libcurl is v7.19.0 or more recent.
+* bool $tcp_keepalive
+ Whether to use TCP keepalive. Available if libcurl is v7.25.0 or more recent.
+* int $tcp_keepidle
+ Seconds to wait before sending keepalive probes. Available if libcurl is v7.25.0 or more recent.
+* int $tcp_keepintvl
+ Interval in seconds to wait between sending keepalive probes. Available if libcurl is v7.25.0 or more recent.
+
+### Authentication
+
+* string $httpauth
+ user:password
+* int $httpauthtype
+ See http\Client\Curl::AUTH_* constants.
+
+### Redirection
+
+* int $redirect
+ How many redirects to follow.
+* bool $unrestricted_auth
+ Whether to keep sending authentication credentials on redirects to different hosts.
+* int $postredir
+ See http\Client\Curl::POSTREDIR_* constants. Available if libcurl is v7.19.1 or more recent.
+
+### Retries
+
+* int $retrycount
+ Retry this often.
+* float $retrydelay
+ Pause this number of seconds between retries.
+
+### Special headers
+
+* string $referer
+ Custom Referer header.
+* bool $autoreferer
+ Whether to automatically send referers.
+* string $useragent
+ Custom User-Agent header.
+* string $etag
+ Custom ETag.
+* bool $compress
+ Whether to request compressed content (through Accept-Encoding).
+* int $lastmodified
+ Custom If-(Un)Modified since time. If less than zero, the current time will be added.
+
+### Resume/Ranges
+
+* int $resume
+ Resume from this byte offset.
+* array $range
+ Fetch specific ranges (if server supports byte ranges).
+
+### Cookies
+
+* bool $encodecookies
+ Whether to URLencode cookies.
+* array $cookies
+ List of custom cookies in the form ["name" => "value"].
+* bool $cookiesession
+ Ignore previous session cookies to be loaded from $cookiestore.
+* string $cookiestore
+ Path to a Netscape cookie file, from which cookies will be loaded resp. to which cookies will be written.
+
+### Timeouts
+
+* float $timeout
+ Seconds the complete transfer may take.
+* float $connecttimeout
+ Seconds the connect may take.
+
+### SSL
+
+* array $ssl
+ Subarray of SSL related options:
+ * string $cert
+ SSL certificate file.
+ * string $certtype
+ Certificate type (DER, PEM). (Secure Transport additionally supports P12).
+ * string $key
+ Private key file.
+ * string $keytype
+ PK type (PEM, DER, ENG).
+ * string $keypasswd
+ The password for the private key.
+ * string $engine
+ Crypto engine to use for the private key.
+ * int $version
+ See http\Client\Curl::SSL_VERSION_* constants.
+ * bool $verifypeer
+ Whether to apply peer verification.
+ * bool $verifyhost
+ Whether to apply host verification.
+ * string $cipher_list
+ One or more cipher strings separated by colons.
+ * string $cainfo
+ CA bundle to verify the peer with.
+ * string $capath
+ Directory with prepared CA certs to verify the peer with.
+ * string $random_file
+ A file used to read from to seed the random engine.
+ * string $egdsocket
+ A Entropy Gathering Daemon socket.
+ * string $issuercert
+ CA PEM cert for peer verification. Available if libcurl is v7.19.0 or more recent.
+ * string $crlfile
+ File with the concatenation of CRL in PEM format. Available if libcurl was built with OpenSSL support.
+ * bool $certinfo
+ Enable gathering of SSL certificate chain information. Available if libcurl is v7.19.1 or more recent.
+