solution: connects to remote dshackle

src/main/kotlin/io/emeraldpay/dshackle/upstream/ChainUpstreams.kt

@@ -0,0 +1,72 @@
+package io.emeraldpay.dshackle.upstream
+
+import io.emeraldpay.grpc.Chain
+import org.slf4j.LoggerFactory
+import java.lang.IllegalStateException
+import java.time.Duration
+
+class ChainUpstreams (
+        val chain: Chain,
+        private val upstreams: MutableList<Upstream>
+) : AggregatedUpstreams() {
+
+    private val log = LoggerFactory.getLogger(ChainUpstreams::class.java)
+    private var seq = 0
+    private var head: EthereumHead
+
+    init {
+        head = updateHead()
+    }
+
+    internal fun updateHead(): EthereumHead {
+        return if (upstreams.size == 1) {
+            upstreams.first().getHead()
+        } else {
+            EthereumHeadMerge(upstreams.map { it.getHead() })
+        }
+    }
+
+    override fun getAll(): List<Upstream> {
+        return upstreams
+    }
+
+    override fun addUpstream(upstream: Upstream) {
+        upstreams.add(upstream)
+        head = updateHead()
+    }
+
+    override fun getApis(quorum: Int): Iterator<EthereumApi> {
+        val i = seq++
+        if (seq >= Int.MAX_VALUE / 2) {
+            seq = 0
+        }
+        return QuorumApi(upstreams, 1, seq)
+    }
+
+    override fun getApi(): EthereumApi {
+        return getApis(1).next()
+    }
+
+    override fun getHead(): EthereumHead {
+        return head
+    }
+
+    fun printStatus() {
+        var height: Long = -1
+        try {
+            height = head.getHead().block(Duration.ofSeconds(1))?.number ?: -1
+        } catch (e: IllegalStateException) {
+            //timout
+        } catch (e: Exception) {
+            log.warn("Head processing error: ${e.javaClass} ${e.message}")
+        }
+        val statuses = upstreams.map { it.getStatus() }
+                .groupBy { it }
+                .map { "${it.key.name}/${it.value.size}" }
+                .joinToString(",")
+
+        log.info("State of ${chain.chainCode}: height=$height, status=$statuses")
+    }
+
+
+}