old_contents: 'use strict';
  
  var defaults = require('./../defaults');
  var utils = require('./../utils');
  var buildUrl = require('./../helpers/buildUrl');
  var transformData = require('./../helpers/transformData');
  var http = require('http');
  var https = require('https');
  var url = require('url');
  var pkg = require('./../../package.json');
  var Buffer = require('buffer').Buffer;
  
  module.exports = function httpAdapter(resolve, reject, config) {
    // Transform request data
    var data = transformData(
      config.data,
      config.headers,
      config.transformRequest
    );
  
    // Merge headers
    var headers = utils.merge(
      defaults.headers.common,
      defaults.headers[config.method] || {},
      config.headers || {}
    );
  
    // Set User-Agent (required by some servers)
    // Only set header if it hasn't been set in config
    // See https://github.com/mzabriskie/axios/issues/69
    if (!headers['User-Agent'] && !headers['user-agent']) {
      headers['User-Agent'] = 'axios/' + pkg.version;
    }
  
    if (data) {
      if (utils.isArrayBuffer(data)) {
        data = new Buffer(new Uint8Array(data));
      } else if (utils.isString(data)) {
        data = new Buffer(data, 'utf-8');
      } else {
        return reject(new Error('Data after transformation must be a string or an ArrayBuffer'));
      }
  
      // Add Content-Length header if data exists
      headers['Content-Length'] = data.length;
    }
  
    // Parse url
    var parsed = url.parse(config.url);
    var options = {
      host: parsed.hostname,
      port: parsed.port,
      path: buildUrl(parsed.path, config.params).replace(/^\?/, ''),
      method: config.method,
      headers: headers,
      agent: config.agent
    };
  
    // Create the request
    var transport = parsed.protocol === 'https:' ? https : http;
    var req = transport.request(options, function (res) {
      var responseBuffer = [];
      res.on('data', function (chunk) {
        responseBuffer.push(chunk);
      });
  
      res.on('end', function () {
        var data = Buffer.concat(responseBuffer);
        if (config.responseType !== 'arraybuffer') {
          data = data.toString('utf8');
        }
        var response = {
          data: transformData(
            data,
            res.headers,
            config.transformResponse
          ),
          status: res.statusCode,
          statusText: res.statusMessage,
          headers: res.headers,
          config: config
        };
  
        // Resolve or reject the Promise based on the status
        (res.statusCode >= 200 && res.statusCode < 300 ?
          resolve :
          reject)(response);
      });
    });
  
    // Handle errors
    req.on('error', function (err) {
      reject(err);
    });
  
    // Handle request timeout
    req.setTimeout(config.timeout, function () {
      req.abort();
    });
  
    // Send the request
    req.end(data);
  };
  
new_contents: 'use strict';
  
  var defaults = require('./../defaults');
  var utils = require('./../utils');
  var buildUrl = require('./../helpers/buildUrl');
  var transformData = require('./../helpers/transformData');
  var http = require('http');
  var https = require('https');
  var url = require('url');
  var pkg = require('./../../package.json');
  var Buffer = require('buffer').Buffer;
  
  module.exports = function httpAdapter(resolve, reject, config) {
    // Transform request data
    var data = transformData(
      config.data,
      config.headers,
      config.transformRequest
    );
  
    // Merge headers
    var headers = utils.merge(
      defaults.headers.common,
      defaults.headers[config.method] || {},
      config.headers || {}
    );
  
    // Set User-Agent (required by some servers)
    // Only set header if it hasn't been set in config
    // See https://github.com/mzabriskie/axios/issues/69
    if (!headers['User-Agent'] && !headers['user-agent']) {
      headers['User-Agent'] = 'axios/' + pkg.version;
    }
  
    if (data) {
      if (utils.isArrayBuffer(data)) {
        data = new Buffer(new Uint8Array(data));
      } else if (utils.isString(data)) {
        data = new Buffer(data, 'utf-8');
      } else {
        return reject(new Error('Data after transformation must be a string or an ArrayBuffer'));
      }
  
      // Add Content-Length header if data exists
      headers['Content-Length'] = data.length;
    }
  
    // Parse url
    var parsed = url.parse(config.url);
    var options = {
      host: parsed.hostname,
      port: parsed.port,
      path: buildUrl(parsed.path, config.params, config.paramsSerializer).replace(/^\?/, ''),
      method: config.method,
      headers: headers,
      agent: config.agent
    };
  
    // Create the request
    var transport = parsed.protocol === 'https:' ? https : http;
    var req = transport.request(options, function (res) {
      var responseBuffer = [];
      res.on('data', function (chunk) {
        responseBuffer.push(chunk);
      });
  
      res.on('end', function () {
        var data = Buffer.concat(responseBuffer);
        if (config.responseType !== 'arraybuffer') {
          data = data.toString('utf8');
        }
        var response = {
          data: transformData(
            data,
            res.headers,
            config.transformResponse
          ),
          status: res.statusCode,
          statusText: res.statusMessage,
          headers: res.headers,
          config: config
        };
  
        // Resolve or reject the Promise based on the status
        (res.statusCode >= 200 && res.statusCode < 300 ?
          resolve :
          reject)(response);
      });
    });
  
    // Handle errors
    req.on('error', function (err) {
      reject(err);
    });
  
    // Handle request timeout
    req.setTimeout(config.timeout, function () {
      req.abort();
    });
  
    // Send the request
    req.end(data);
  };
  
subject: add config.paramsSerializer to http adapter