bson/src/main/org/bson/codecs/DecoderContext.java
public <T> T decodeWithChildContext(final Decoder<T> decoder, final BsonReader reader) {
        return decoder.decode(reader, DEFAULT_CONTEXT);
    }
public <T> T decodeWithChildContext(final Decoder<T> decoder, final BsonReader reader) {
        return decoder.decode(reader, DEFAULT_CONTEXT);
    }
Creates a child context and then deserializes using the reader.

@param decoder the decoder to decode with
@param reader the reader to decode to
@param <T> the type of the decoder
@return the decoded value
@since 3.5