docs: function downloadTools(toolDirName) {
  	if(!toolDirName){
  		toolDirName = 'platform-tools';
  	}
  	return new Promise((resolve, reject) =>{
  		const androidToolZipPath = path.join(WORKING_DIRECTORY, 'android-sdk.zip');
  		const androidToolDir = path.join(WORKING_DIRECTORY, toolDirName);
  		const downloadUrl = helper.getOSUrl();
  		console.log(`Downloading Android platform tools from: ${downloadUrl}`);
  		const requestOptions = {timeout: 30000, 'User-Agent': helper.getUserAgent()};
  		request(downloadUrl, requestOptions)
  			.on('error', (error)  => {
  				debug(`Request Error ${error}`);
  				reject(error);
  			})
  			.on('response', (response)  => {
  				const len = parseInt(response.headers['content-length'], 10);
  				let bar = new ProgressBar('  downloading [:bar] :percent :etas', {
  					complete: '=',
  					incomplete: ' ',
  					width: 20,
  					total: len
  				});
  
  				response.on('data', function (chunk) {
  					if (chunk.length){
  						bar.tick(chunk.length);
  					}
  				});
  
  				response.on('end', function () {
  					console.log('\n');
  				});
  				debug(response.statusCode);
  				debug(response.headers['content-type']);
  			})
  			.pipe(fs.createWriteStream(androidToolZipPath))
  			.on('finish', ()  => {
  				debug('wstream finished');
  				console.log('Extracting Android SDK');
  				extract(androidToolZipPath, {dir: WORKING_DIRECTORY},(error) =>{
  					if(error){
  						debug(`Extraction failed: ${error}`);
  						reject(error);
  					} else{
  						console.log('Extraction complete');
  						debug('downloadSDK complete');
  						if(zipCache !== null){
  							resolve({path:androidToolDir, message:'downloadSDK complete', zipPath:androidToolZipPath});
  							return;
  						}
  						fs.remove(androidToolZipPath, err => {
  							if (err) {
  								console.error(`removing zip file failed: ${err}`);
  								reject(err);
  							} else {
  								console.log('Removed platform-tools zip file, please specify ADB_ZIP_CACHE if you wish to keep it');
  								resolve({path:androidToolDir, message:'downloadSDK complete'});
  							}
  						});
  					}
  				});
  			});
  	});
  }