parseLine(line, event) {
        if (line.length === 0) {
          return;
        }
        const colonPosition = line.indexOf(COLON);
        if (colonPosition === 0) {
          return;
        }
        let field = "";
        let value = "";
        if (colonPosition !== -1) {
          field = line.subarray(0, colonPosition).toString("utf8");
          let valueStart = colonPosition + 1;
          if (line[valueStart] === SPACE) {
            ++valueStart;
          }
          value = line.subarray(valueStart).toString("utf8");
        } else {
          field = line.toString("utf8");
          value = "";
        }
        switch (field) {
          case "data":
            if (event[field] === void 0) {
              event[field] = value;
            } else {
              event[field] += `
${value}`;
            }
            break;
          case "retry":
            if (isASCIINumber(value)) {
              event[field] = value;
            }
            break;
          case "id":
            if (isValidLastEventId(value)) {
              event[field] = value;
            }
            break;
          case "event":
            if (value.length > 0) {
              event[field] = value;
            }
            break;
        }
      }
@param {Buffer} line
@param {EventStreamEvent} event