code: async function getRawContent(dir, ref, pathName, includeUncommitted) {
    return resolveBlob(dir, ref, pathName, includeUncommitted)
      .then(oid => git.readObject({ dir, oid, format: 'content' }).object);
  }
docs: Returns the contents of the file at revision `ref` and `pathName`
  
  @param {string} dir git repo path
  @param {string} ref reference (branch, tag or commit sha)
  @param {string} filePath relative path to file
  @param {boolean} includeUncommitted include uncommitted changes in working dir
  @returns {Promise<Buffer>} content of specified file
  @throws {GitError} `err.code === 'TreeOrBlobNotFoundError'`: resource not found
  `err.code === 'ResolveRefError'`: invalid reference