public com.google.protobuf.ByteString getSchemeBytes() {
        java.lang.Object ref = scheme_;
        if (ref instanceof String) {
          com.google.protobuf.ByteString b =
              com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
          scheme_ = b;
          return b;
        } else {
          return (com.google.protobuf.ByteString) ref;
        }
      }
<pre>
Required. Specify the encryption scheme, supported schemes:
- `cenc` - AES-CTR subsample
- `cbcs`- AES-CBC subsample pattern
</pre>

<code>string scheme = 1 [(.google.api.field_behavior) = REQUIRED];</code>

@return The bytes for scheme.
java-video-live-stream/proto-google-cloud-live-stream-v1/src/main/java/com/google/cloud/video/livestream/v1/Encryption.java