let contentTypeIndex = _.findIndex(request.headers.members, { key: 'Content-Type' }),
    formDataHeader = `multipart/form-data; boundary=${FORM_DATA_BOUNDARY}`,
    headers = '';
 
  if (contentTypeIndex >= 0) {
    if (request.headers.members[contentTypeIndex].value === 'multipart/form-data' || request.body.mode === 'formdata') {
      request.headers.members[contentTypeIndex].value = formDataHeader;
    }
  }
 
  _.forEach(request.headers.members, (header) => {
    header.key = header.key.trim();
  });
  headers = convertPropertyListToString(request.headers, '\n', false);
  if (request.body.mode === 'formdata' && contentTypeIndex < 0) {
    headers += `Content-Type: ${formDataHeader}`;
  }
  return headers;
}