code: public Blob createBlob(String bucketName, String blobName) {
      // [START createBlob]
      BlobId blobId = BlobId.of(bucketName, blobName);
      BlobInfo blobInfo = BlobInfo.newBuilder(blobId).setContentType("text/plain").build();
      Blob blob = storage.create(blobInfo);
      // [END createBlob]
      return blob;
    }
docs: [VARIABLE "my_blob_name"]