lib/plugins/aws/provider/awsProvider.js/AwsProvider/constructor
class AwsProvider:  constructor(serverless) {
    this.serverless = serverless;
    this.sdk = AWS;
    this.provider = this; // only load plugin in an AWS service context
    this.serverless.setProvider('aws', this);

    // Use HTTPS Proxy (Optional)
    const proxy = process.env.proxy
      || process.env.HTTP_PROXY
      || process.env.http_proxy
      || process.env.HTTPS_PROXY
      || process.env.https_proxy;

    if (proxy) {
      const proxyOptions = url.parse(proxy);
      proxyOptions.secureEndpoint = true;
      AWS.config.httpOptions.agent = new HttpsProxyAgent(proxyOptions);
    }

    // Configure the AWS Client timeout (Optional).  The default is 120000 (2 minutes)
    const timeout = process.env.AWS_CLIENT_TIMEOUT || process.env.aws_client_timeout;
    if (timeout) {
      AWS.config.httpOptions.timeout = parseInt(timeout, 10);
    }
  }