@Override
    public ByteBuf toByteBuf(HttpData in) {
        if (base64Decoder != null) {
            return base64Decoder.decode(in.byteBuf());
        } else {
            return in.byteBuf();
        }
    }
Construct an {@link ArmeriaMessageDeframer} for reading messages out of a gRPC request or
response with the specified parameters.
grpc-protocol/src/main/java/com/linecorp/armeria/common/grpc/protocol/ArmeriaMessageDeframer.java