src/vs/workbench/contrib/output/electron-sandbox/outputChannelModelService.ts/OutputChannelBackedByFile/loadFile
class OutputChannelBackedByFile:	private loadFile(): Promise<string> {
		return this.fileService.readFile(this.file, { position: this.startOffset })
			.then(content => this.appendedMessage ? content.value + this.appendedMessage : content.value.toString());
	}