message: Improve Server methods' return value.
diff: @@ -1332,7 +1332,7 @@ static PHP_METHOD(swoole_http_request, rawContent)
  #endif
  else
  {
  - RETURN_FALSE;
  + RETURN_EMPTY_STRING();
  }
  }
  @@ -1473,12 +1473,7 @@ static PHP_METHOD(swoole_http_response, write)
  static http_context* http_get_context(zval *zobject, int check_end)
  {
  http_context *ctx = (http_context *) swoole_get_object(zobject);
  - if (!ctx)
  - {
  - swoole_php_fatal_error(E_WARNING, "Http request is finished.");
  - return NULL;
  - }
  - if (check_end && ctx->end)
  + if (!ctx || (check_end && ctx->end))
  {
  swoole_php_fatal_error(E_WARNING, "Http request is finished.");
  return NULL;
  @@ -1826,18 +1821,17 @@ static PHP_METHOD(swoole_http_response, initHeader)
  {
  swoole_http_server_array_init(header, response);
  }
  -
  zval *zcookie = sw_zend_read_property(swoole_http_response_ce_ptr, zresponse_object, ZEND_STRL("cookie"), 1);
  if (!ZVAL_IS_ARRAY(zcookie))
  {
  swoole_http_server_array_init(cookie, response);
  }
  -
  zval *ztrailer = sw_zend_read_property(swoole_http_response_ce_ptr, zresponse_object, ZEND_STRL("trailer"), 1);
  if (!ZVAL_IS_ARRAY(ztrailer))
  {
  swoole_http_server_array_init(trailer, response);
  }
  + RETURN_TRUE;
  }
  static PHP_METHOD(swoole_http_response, end)
  @@ -2201,6 +2195,7 @@ static PHP_METHOD(swoole_http_response, status)
  ctx->response.reason = (char *) emalloc(SW_MEM_ALIGNED_SIZE(reason_len + 1));
  strncpy(ctx->response.reason, reason, reason_len);
  }
  + RETURN_TRUE;
  }
  static PHP_METHOD(swoole_http_response, header)
  @@ -2260,7 +2255,7 @@ static PHP_METHOD(swoole_http_response, header)
  {
  add_assoc_stringl_ex(zheader, k, klen, v, vlen);
  }
  -
  + RETURN_TRUE;
  }
  #ifdef SW_USE_HTTP2
  @@ -2319,6 +2314,7 @@ static PHP_METHOD(swoole_http_response, trailer)
  {
  add_assoc_stringl_ex(ztrailer, k, klen, v, vlen);
  }
  + RETURN_TRUE;
  }
  #endif
  @@ -2356,6 +2352,7 @@ static PHP_METHOD(swoole_http_response, create)
  sw_copy_to_stack(ctx->response.zobject, ctx->response._zobject);
  zend_update_property_long(swoole_http_response_ce_ptr, return_value, ZEND_STRL("fd"), ctx->fd);
  + RETURN_TRUE;
  }
  static PHP_METHOD(swoole_http_response, redirect)
  @@ -2389,7 +2386,7 @@ static PHP_METHOD(swoole_http_response, redirect)
  ZVAL_STRINGL(&key, "Location", 8);
  sw_zend_call_method_with_2_params(getThis(), NULL, NULL, "header", return_value, &key, url);
  zval_ptr_dtor(&key);
  - if (!ZVAL_IS_NULL(return_value)) // TODO: return true
  + if (!Z_BVAL_P(return_value))
  {
  return;
  }
  