src/vs/platform/files/common/fileService.ts/FileService/readFileUnbuffered
class FileService:	private readFileUnbuffered(provider: IFileSystemProviderWithFileReadWriteCapability, resource: URI, options?: IReadFileStreamOptions): VSBufferReadableStream {
		const stream = newWriteableStream<VSBuffer>(data => VSBuffer.concat(data));

		// Read the file into the stream async but do not wait for
		// this to complete because streams work via events
		(async () => {
			try {
				let buffer = await provider.readFile(resource);

				// respect position option
				if (options && typeof options.position === 'number') {
					buffer = buffer.slice(options.position);
				}

				// respect length option
				if (options && typeof options.length === 'number') {
					buffer = buffer.slice(0, options.length);
				}

				// Throw if file is too large to load
				this.validateReadFileLimits(resource, buffer.byteLength, options);

				// End stream with data
				stream.end(VSBuffer.wrap(buffer));
			} catch (err) {
				stream.error(err);
				stream.end();
			}
		})();

		return stream;
	}