private static MethodHandle lookupUnmapMethodHandle() {
        final MethodHandles.Lookup lookup = lookup();
        try {
            if (Java.IS_JAVA9_COMPATIBLE)
                return unmapJava9(lookup);
            else
                return unmapJava7Or8(lookup);
        } catch (ReflectiveOperationException | RuntimeException e1) {
            throw new UnsupportedOperationException("Unmapping is not supported on this platform, because internal " +
                "Java APIs are not compatible with this Kafka version", e1);
        }
    }
Unmap the provided mapped or direct byte buffer.

This buffer cannot be referenced after this call, so it's highly recommended that any fields referencing it
should be set to null.

@throws IllegalArgumentException if buffer is not mapped or direct.
clients/src/main/java/org/apache/kafka/common/utils/ByteBufferUnmapper.java