How do I install http_request2 package via composer?

I saw that http_request2 is on github and it has a composer.json file. But
there is no description on how to add http_request2 to my project via
composer.

So I added these sections to my composer.json:

"repositories": [
        {
            "type": "pear",
            "url": "pear.php.net"
        }
    ],
    "require": {
        "pear/http_request2": "*"
    },

But composer tells me:

$ sudo composer update
Loading composer repositories with package information
Initializing PEAR repository http://pear.php.net
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Installation request for pear/http_request2 * -> satisfiable by
fpoirotte/http_request2[2.1.1-patch1].
    - fpoirotte/http_request2 2.1.1-patch1 requires pear/pear_exception
dev-master -> no matching package found.

Why is pear_exception not found? Can someone add composer instructions to
the github page? https://github.com/pear/HTTP_Request2

Thanks,
Ty