建议：
拷贝 /vendor/joanhey/adapterman/src/start.php 文件至项目根目录，并修改文件内容

use Adapterman\Adapterman;
use Adapterman\Http;
use Workerman\Worker;
use Workerman\Timer;

require __DIR__ . '/vendor/autoload.php';

Adapterman::init();

require __DIR__ . '/vendor/joanhey/adapterman/src/frameworks/index.php';

Worker::$logFile = __DIR__ . '/runtime/workerman.log';
Worker::$pidFile = __DIR__ . '/runtime/workerman.pid';
Worker::$statusFile = __DIR__ . '/runtime/workerman.status';
Worker::$stdoutFile = __DIR__ . '/runtime/workerman_stdout.log';

$http_worker = (new Worker('http://0.0.0.0:8080'));
$http_worker->count = 4;
$http_worker->name = 'AdapterMan';

$http_worker->onWorkerStart = function (Worker $worker) {
    if ($worker->id === 0) {
        Timer::add(600, function(){
            Http::tryGcSessions();
        });
    }
};

$http_worker->onMessage = static function ($connection, $request) {
    $connection->send(run());
};

Worker::runAll();

为什么你的workerman5.1版本的可以安装 composer require joanhey/adapterman ，我这边项目按照提示 Your requirements could not be resolved to an installable set of packages.

Problem 1

• Root composer.json requires joanhey/adapterman * -> satisfiable by joanhey/adapterman[v0.2, ..., 0.7.0].
• joanhey/adapterman[v0.2, ..., 0.5.5] require workerman/workerman ^3.5 -> found workerman/workerman[v3.5.0, ..., v3.5.35] but it conflicts with your root composer.json require (^v5.1.0).
• joanhey/adapterman[0.6, ..., 0.7.0] require workerman/workerman ^4.1 -> found workerman/workerman[v4.1.0, ..., v4.2.1] but it conflicts with your root composer.json require (^v5.1.0).

Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.
You can also try re-running composer require with an explicit version constraint, e.g. "composer require joanhey/adapterman:*" to figure out if any version is installable, or "composer require joanhey/adapterman:^2.1" if you know which you need.