message: support sftp sink
diff: }
  }
  },
  + "SftpWriteSettings": {
  + "description": "Sftp write settings.",
  + "type": "object",
  + "allOf": [
  + {
  + "$ref": "#/definitions/StoreWriteSettings"
  + }
  + ],
  + "properties": {
  + "operationTimeout": {
  + "description": "Specifies the timeout for writing each chunk to SFTP server. Default value: 01:00:00 (one hour). Type: string (or Expression with resultType string).",
  + "type": "object"
  + }
  + }
  + },
  "GoogleCloudStorageReadSettings": {
  "description": "Google Cloud Storage read settings.",
  "type": "object",
  