openrtb-core/src/main/java/com/google/openrtb/json/OpenRtbJsonWriter.java
public void writeBidRequest(BidRequest req, Writer writer) throws IOException {
    JsonGenerator gen = factory().getJsonFactory().createGenerator(writer);
    writeBidRequest(req, gen);
  }
public void writeBidRequest(BidRequest req, Writer writer) throws IOException {
    JsonGenerator gen = factory().getJsonFactory().createGenerator(writer);
    writeBidRequest(req, gen);
  }
Serializes a {@link BidRequest} to JSON, streamed into an {@link Writer}.

@see JsonFactory#createGenerator(Writer)