initWithBoundary(str) {
		    this.boundary = Buffer.from(`\r\n--${str}`);
		    this.lookbehind = Buffer.alloc(this.boundary.length + 8);
		    this.state = STATE.START;
		    this.boundaryChars = {};

		    for (let i = 0; i < this.boundary.length; i++) {
		      this.boundaryChars[this.boundary[i]] = true;
		    }
		  }
Module of mixed-in functions shared between node and client code