Clone a com.squareup.moshi.JsonReader object

MoshiHelper.java

import com.squareup.moshi.JsonReader;
import com.squareup.moshi.JsonWriter;
import okio.Buffer;
import okio.BufferedSink;

import java.io.IOException;

public final class MoshiHelper {

    public static void dump(JsonReader reader, BufferedSink sink) throws IOException {
        JsonWriter writer = JsonWriter.of(sink);
        int nested = 0;
        while (reader.peek() != JsonReader.Token.END_DOCUMENT) {
            switch (reader.peek()) {
                case BEGIN_ARRAY:
                    nested++;
                    reader.beginArray();
                    writer.beginArray();
                    break;
                case END_ARRAY:
                    reader.endArray();
                    writer.endArray();
                    if (0 == --nested) return;
                    break;
                case BEGIN_OBJECT:
                    nested++;
                    reader.beginObject();
                    writer.beginObject();
                    break;
                case END_OBJECT:
                    reader.endObject();
                    writer.endObject();
                    if (0 == --nested) return;
                    break;
                case NAME:
                    writer.name(reader.nextName());
                    break;
                case NUMBER:
                    try {
                        writer.value(reader.nextLong());
                    } catch (Exception ignored) {
                        writer.value(reader.nextDouble());
                    }
                    break;
                case BOOLEAN:
                    writer.value(reader.nextBoolean());
                    break;
                case STRING:
                    writer.value(reader.nextString());
                    break;
                case NULL:
                    reader.nextNull();
                    writer.nullValue();
                    break;
            }
        }
    }

    public static JsonReader copyOf(Buffer buffer) {
        Buffer forked = new Buffer();
        buffer.copyTo(forked, 0, buffer.size());
        return JsonReader.of(forked);
    }
}

To clone a JsonReader:

1. Dumps token stream from JsonReader into a JsonWriter that writes to a buffer
2. Create a new JsonReader from the buffer.

Buffer buffer = new Buffer();
MoshiHelper.dump(reader, buffer);
JsonReader copiedReader = MoshiHelper.copyOf(buffer);

Thanks a lot for the effort!
Looks like they've added this feature with a peekJson():
square/moshi@69d4f40#diff-4ac32a78649ca5bdd8e0ba38b7006a1eR14