RESOURCE_REQUEST

The `ResourceRequest` event allows client to observe resource requests made by a `map` or `map snapshotter` objects. ``` text Event data format (Object): . ├── data-source - String ("resource-loader" | "network" | "database" | "asset" | "file-system") ├── request - Object │ ├── url - String │ ├── kind - String ("unknown" | "style" | "source" | "tile" | "glyphs" | "sprite-image" | "sprite-json" | "image") │ ├── priority - String ("regular" | "low") │ └── loading-method - Array ["cache" | "network"] ├── response - optional Object │ ├── no-content - Boolean │ ├── not-modified - Boolean │ ├── must-revalidate - Boolean │ ├── source - String ("network" | "cache" | "tile-store" | "local-file") │ ├── size - Number (size in bytes) │ ├── modified - optional String, rfc1123 timestamp │ ├── expires - optional String, rfc1123 timestamp │ ├── etag - optional String │ └── error - optional Object │ ├── reason - String ("success" | "not-found" | "server" | "connection" | "rate-limit" | "in-offline-mode" | "other") │ └── message - String └── cancelled - Boolean ```