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=head2 C<set_preempt_threshold( $val )>

Sets the number of C<maybe_yield> increments before a forced yield occurs. Default is 0 (preemption disabled).

=head1 Class Methods

=head2 C<tid( )>

Returns the unique OS Thread ID of the main interpreter thread.

=head2 C<current_fid( )>

Returns the unique numeric ID of the currently executing fiber, or -1 if called from the "root" (main) context.

=head2 C<root( )>

Returns a proxy object representing the initial execution context. This is useful for C<transfer( )>ing control back to
the main thread from a symmetric coroutine.

=head1 Acme::Parataxis OBJECT METHODS

=head2 C<fid( )>

Returns the unique numeric ID of the fiber object.

=head2 C<is_done( )>

Returns true if the fiber has finished execution (either by returning or dying). Once a fiber is done, its internal ID
is released and it can no longer be called.

=head1 Acme::Parataxis::Future OBJECT METHODS

=head2 C<await( )>

Suspends the current fiber until the future is ready. Returns the result or B<dies> if the task encountered an error.

=head2 C<is_ready( )>

Returns true if the task associated with the future has completed.

=head2 C<result( )>

Returns the task result immediately. Croaks if the future is not yet ready.


=head1 INTEGRATING SYNCHRONOUS MODULES

To use synchronous modules (like C<HTTP::Tiny>) in a non-blocking way, you can subclass their handle or transport
methods and use a C<while> loop combined with C<yield('WAITING')>. This ensures the fiber yields control until the
underlying I/O is ready.

    # Example: A cooperative HTTP::Tiny subclass
    {
        package My::HTTP;
        use parent 'HTTP::Tiny';
        sub _open_handle {
            my ($self, $request, $scheme, $host, $port, $peer) = @_;
            return My::HTTP::Handle->new(
                timeout            => $self->{timeout},
                keep_alive         => $self->{keep_alive},
                keep_alive_timeout => $self->{keep_alive_timeout}
            )->connect($scheme, $host, $port, $peer);
        }
        sub request {
            my ($self, $method, $url, $args) = @_;
            my %new_args = %{ $args // {} };
            my $orig_cb = $new_args{data_callback};
            my $content = '';
            $new_args{data_callback} = sub {
                my ($data, $response) = @_;
                if ($orig_cb) { return $orig_cb->($data, $response) }
                $content .= $data;
                return 1;
            };
            my $res = $self->SUPER::request($method, $url, \%new_args);
            $res->{content} = $content unless $orig_cb;
            return $res;
        }
    }
    {
        package My::HTTP::Handle;
        use parent -norequire, 'HTTP::Tiny::Handle';
        use Time::HiRes qw[time];
        sub _do_timeout {
            my ($self, $type, $timeout) = @_;
            $timeout //= $self->{timeout} // 60;
            my $start = time;
            while (1) {
                # Check for readiness NOW (0 timeout)
                return 1 if $self->SUPER::_do_timeout($type, 0);
                # Check for overall timeout
                my $elapsed = time - $start;
                return 0 if $elapsed > $timeout;
                # Suspend fiber and wait for background I/O check
                my $wait = ($timeout - $elapsed) > 0.5 ? 0.5 : ($timeout - $elapsed);
                if ($type eq 'read') {
                    Acme::Parataxis->await_read($self->{fh}, int($wait * 1000));
                } else {
                    Acme::Parataxis->await_write($self->{fh}, int($wait * 1000));
                }
            }
        }
    }

=head1 EXAMPLES

=head2 Cooperative Parallelism

This example demonstrates how to perform multiple HTTP requests concurrently on a single interpretation thread.

    use Acme::Parataxis;
    # ... (See My::HTTP implementation in INTEGRATING SYNCHRONOUS MODULES) ...

    Acme::Parataxis::run(sub {
        my $http = My::HTTP->new(verify_SSL => 0);
        my @urls = qw[http://example.com http://perl.org];

        # Spawn tasks for each URL
        my @futures = map {
            my $url = $_;
            Acme::Parataxis->spawn(sub { $http->get($url)->{status} })