minor #12335 [HttpClient] Add the buffer option to 4.3 too (javiereguiluz)

This PR was merged into the 4.3 branch.

Discussion
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[HttpClient] Add the buffer option to 4.3 too

After merging #12043 I realized we need to document it in 4.3 too.

Commits
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c82e6b8 [HttpClient] Add the buffer option to 4.3 too

Author: javiereguiluz

reference/configuration/framework.rst

@@ -93,6 +93,7 @@ Configuration
   * :ref:`default_options <reference-http-client-default-options>`
 
     * `bindto`_
+    * `buffer`_
     * `cafile`_
     * `capath`_
     * `ciphers`_
@@ -118,6 +119,7 @@ Configuration
     * `auth_bearer`_
     * `base_uri`_
     * `bindto`_
+    * `buffer`_
     * `cafile`_
     * `capath`_
     * `ciphers`_
@@ -781,6 +783,15 @@ bindto
 A network interface name, IP address, a host name or a UNIX socket to use as the
 outgoing network interface.
 
+buffer
+......
+
+**type**: ``bool`` **default**: ``false``
+
+Buffering the response means that you can access its content multiple times
+without performing the request again. Pass ``true`` as the value of this option
+to enable buffering.
+
 cafile
 ......