src/vs/editor/common/model/prefixSumComputer.ts/PrefixSumComputer/constructor
class PrefixSumComputer:	constructor(values: Uint32Array) {
		this.values = values;
		this.prefixSum = new Uint32Array(values.length);
		this.prefixSumValidIndex = new Int32Array(1);
		this.prefixSumValidIndex[0] = -1;
	}