addEntry(entry) {
    if (
      this.compilationState.isCompiling ||
      this.compilationState.isVerifyingCache
    ) {
      throw new Error(
        "The child compiler has already started to compile. " +
          "Please add entries before the main compiler 'make' phase has started or " +
          "after the compilation is done.",
      );
    }
    if (this.compilationState.entries.indexOf(entry) === -1) {
      this.compilationState.entries = [...this.compilationState.entries, entry];
    }
  }
Add a new entry to the next compile run
@param {string} entry