public Builder clearOverwriteWhen() {
        bitField0_ = (bitField0_ & ~0x00000008);
        overwriteWhen_ = 0;
        onChanged();
        return this;
      }
<pre>
When to overwrite objects that already exist in the sink. If not set,
overwrite behavior is determined by
[overwrite_objects_already_existing_in_sink][google.storagetransfer.v1.TransferOptions.overwrite_objects_already_existing_in_sink].
</pre>

<code>.google.storagetransfer.v1.TransferOptions.OverwriteWhen overwrite_when = 4;</code>

@return This builder for chaining.
java-storage-transfer/proto-google-cloud-storage-transfer-v1/src/main/java/com/google/storagetransfer/v1/proto/TransferTypes.java