code: @BetaApi
    public final Disk getDisk(String disk) {
  
      GetDiskHttpRequest request = GetDiskHttpRequest.newBuilder().setDisk(disk).build();
      return getDisk(request);
    }
docs: Returns a specified persistent disk. Gets a list of available persistent disks by making a
  list() request.
  
  <p>Sample code:
  
  <pre><code>
  try (DiskClient diskClient = DiskClient.create()) {
  ProjectZoneDiskName disk = ProjectZoneDiskName.of("[PROJECT]", "[ZONE]", "[DISK]");
  Disk response = diskClient.getDisk(disk.toString());
  }
  </code></pre>
  
  @param disk Name of the persistent disk to return.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails