public ServerBuilder pingInterval(Duration pingInterval) {
        pingIntervalMillis(requireNonNull(pingInterval, "pingInterval").toMillis());
        return this;
    }
Sets the HTTP/2 <a href="https://datatracker.ietf.org/doc/html/rfc7540#section-6.7">PING</a> interval.

<p>Note that this settings is only in effect when {@link #idleTimeoutMillis(long)}} or
{@link #idleTimeout(Duration)} is greater than the specified PING interval.

<p>The minimum allowed PING interval is {@value #MIN_PING_INTERVAL_MILLIS} milliseconds.
{@code 0} means the server will not send PING frames on an HTTP/2 connection.

@throws IllegalArgumentException if the specified {@code pingInterval} is smaller than
                                 {@value #MIN_PING_INTERVAL_MILLIS} milliseconds.
core/src/main/java/com/linecorp/armeria/server/ServerBuilder.java