use Posix.read instead of Glibc.read for timerfd  (#1432)
use Posix.read instead of Glibc.read for timerfd  (#1432)

Motivation:

To read the bytes from timerfd, we use Glibc.read directly but we should use try! Posix.read

Modifications:

Using Posix instead of Glibc for read operation with try! to check for any error.

Result:

Fixes #1341

Co-authored-by: Johannes Weiss <d63540ace140105639c46173690300ccf8e978b5@apple.com>

apple/swift-nio,apple/swift-nio,apple/swift-nio,apple/swift-nio,apple/swift-nio