ReadFileSystem for reading from URLs using fetch.
Supports optional base URL for relative paths.
Automatically detects whether the server supports Range requests.
If Range requests are supported, uses streaming with Range headers for efficient seeking.
If not supported (e.g., Python's SimpleHTTPRequestHandler), falls back to downloading
the entire file into memory first.
ReadFileSystem for reading from URLs using fetch. Supports optional base URL for relative paths.
Automatically detects whether the server supports Range requests. If Range requests are supported, uses streaming with Range headers for efficient seeking. If not supported (e.g., Python's SimpleHTTPRequestHandler), falls back to downloading the entire file into memory first.