src/vs/workbench/contrib/tasks/browser/terminalTaskSystem.ts/TerminalTaskSystem/mergeMaps
class TerminalTaskSystem:	private mergeMaps(mergeInto: Map<string, string>, mergeFrom: Map<string, string>) {
		for (const entry of mergeFrom) {
			if (!mergeInto.has(entry[0])) {
				mergeInto.set(entry[0], entry[1]);
			}
		}
	}