aeron-client/src/main/java/io/aeron/Image.java
public int poll(final FragmentHandler fragmentHandler, final int fragmentLimit)
    {
        if (isClosed)
        {
            return 0;
        }

        final long position = subscriberPosition.get();

        return TermReader.read(
            activeTermBuffer(position),
            (int)position & termLengthMask,
            fragmentHandler,
            fragmentLimit,
            header,
            errorHandler,
            position,
            subscriberPosition);
    }
public int poll(final FragmentHandler fragmentHandler, final int fragmentLimit)
    {
        if (isClosed)
        {
            return 0;
        }

        final long position = subscriberPosition.get();

        return TermReader.read(
            activeTermBuffer(position),
            (int)position & termLengthMask,
            fragmentHandler,
            fragmentLimit,
            header,
            errorHandler,
            position,
            subscriberPosition);
    }
Poll for new messages in a stream. If new messages are found beyond the last consumed position then they
will be delivered to the {@link FragmentHandler} up to a limited number of fragments as specified.
<p>
Use a {@link FragmentAssembler} to assemble messages which span multiple fragments.

@param fragmentHandler to which message fragments are delivered.
@param fragmentLimit   for the number of fragments to be consumed during one polling operation.
@return the number of fragments that have been consumed.
@see FragmentAssembler
@see ImageFragmentAssembler