HevPollableFD: Call pending async callback in destruct.
HevSocket: Call pending async callback in destruct.
HevDNSResolver: Call pending async callback in destruct.
HevDNSResolver: Revert current buffer tracking.
HevSocks5Session: Fix destruct twice.
HevSocks5Session: Revert current buffers tracking.
HevDNSResolver: The pending callback will be called by pollable fd.
HevDNSResolver: Fix destruct called again by pollable fd handler.
HevPollableFD: The destruct may be called again by async handler.
HevSocket: The destruct may be called again by async handler.
HevSocks5Session: The destruct may be called again by async handler.
HevSocket: Fix pending callback result.