src/Http.php
public function buildPostParameters() {
        $parameters = $this->getPostSource();
        if (!is_array($parameters)) {
            return $parameters;
        }
        $binary_data = false;
        foreach ($parameters as $key => $value) {
            if (is_string($value) && strpos($value, '@')
                === 0 && is_file(substr($value, 1))) {
                $binary_data = true;
                if (class_exists('CURLFile')) {
                    $parameters[$key] = new \CURLFile(substr($value, 1));
                }
            } elseif ($value instanceof \CURLFile) {
                $binary_data = true;
            }
        }
        if ($binary_data) {
            return $parameters;
        }
        return http_build_query($parameters, '', '&');
    }
public function buildPostParameters() {
        $parameters = $this->getPostSource();
        if (!is_array($parameters)) {
            return $parameters;
        }
        $binary_data = false;
        foreach ($parameters as $key => $value) {
            if (is_string($value) && strpos($value, '@')
                === 0 && is_file(substr($value, 1))) {
                $binary_data = true;
                if (class_exists('CURLFile')) {
                    $parameters[$key] = new \CURLFile(substr($value, 1));
                }
            } elseif ($value instanceof \CURLFile) {
                $binary_data = true;
            }
        }
        if ($binary_data) {
            return $parameters;
        }
        return http_build_query($parameters, '', '&');
    }
生成post 提交数据
@return array|string
@throws Exception