Small improvements after dynamic head introduction

- add injection of schedulers for dynamic heads
- more logging
- replace onBackpressureBuffer to directBestEffort multicast sink

src/test/groovy/io/emeraldpay/dshackle/test/MultistreamHolderMock.groovy

@@ -34,6 +34,7 @@ import io.emeraldpay.dshackle.BlockchainType
 import io.emeraldpay.dshackle.Chain
 
 import org.jetbrains.annotations.NotNull
+import reactor.core.scheduler.Schedulers
 
 class MultistreamHolderMock implements MultistreamHolder {
 
@@ -50,7 +51,7 @@ class MultistreamHolderMock implements MultistreamHolder {
                 if (up instanceof EthereumPosMultiStream) {
                     upstreams[chain] = up
                 } else if (up instanceof EthereumPosRpcUpstream) {
-                    upstreams[chain] = new EthereumPosMultiStream(chain, [up as EthereumPosRpcUpstream], Caches.default())
+                    upstreams[chain] = new EthereumPosMultiStream(chain, [up as EthereumPosRpcUpstream], Caches.default(), Schedulers.boundedElastic())
                 } else {
                     throw new IllegalArgumentException("Unsupported upstream type ${up.class}")
                 }
@@ -98,7 +99,7 @@ class MultistreamHolderMock implements MultistreamHolder {
         Head customHead = null
 
         EthereumMultistreamMock(@NotNull Chain chain, @NotNull List<EthereumPosRpcUpstream> upstreams, @NotNull Caches caches) {
-            super(chain, upstreams, caches)
+            super(chain, upstreams, caches, Schedulers.boundedElastic())
         }
 
         EthereumMultistreamMock(@NotNull Chain chain, @NotNull List<EthereumPosRpcUpstream> upstreams) {

src/test/groovy/io/emeraldpay/dshackle/test/TestingCommons.groovy

@@ -38,6 +38,7 @@ import io.emeraldpay.dshackle.Chain
 import io.micrometer.core.instrument.MeterRegistry
 import io.micrometer.core.instrument.logging.LoggingMeterRegistry
 import org.apache.commons.lang3.StringUtils
+import reactor.core.scheduler.Schedulers
 
 import java.time.Instant
 
@@ -84,7 +85,7 @@ class TestingCommons {
     }
 
     static Multistream multistream(EthereumPosRpcUpstreamMock up) {
-        return new EthereumPosMultiStream(Chain.ETHEREUM, [up], Caches.default()).tap {
+        return new EthereumPosMultiStream(Chain.ETHEREUM, [up], Caches.default(), Schedulers.boundedElastic()).tap {
             start()
         }
     }
@@ -105,11 +106,11 @@ class TestingCommons {
     }
 
     static Multistream multistreamWithoutUpstreams(Chain chain) {
-        return new EthereumPosMultiStream(chain, [], emptyCaches().getCaches(chain))
+        return new EthereumPosMultiStream(chain, [], emptyCaches().getCaches(chain), Schedulers.boundedElastic())
     }
 
     static Multistream multistreamClassicWithoutUpstreams(Chain chain) {
-        return new EthereumMultistream(chain, [], emptyCaches().getCaches(chain))
+        return new EthereumMultistream(chain, [], emptyCaches().getCaches(chain), Schedulers.boundedElastic())
     }
 
     static FileResolver fileResolver() {
@@ -148,6 +149,4 @@ class TestingCommons {
     }
 
     static MeterRegistry meterRegistry = new LoggingMeterRegistry()
-
-    static CallTargetsHolder callTargetsHolder = new CallTargetsHolder()
 }

src/test/groovy/io/emeraldpay/dshackle/upstream/MultistreamSpec.groovy

@@ -37,6 +37,7 @@ import io.emeraldpay.dshackle.Chain
 import org.jetbrains.annotations.NotNull
 import reactor.core.publisher.Flux
 import reactor.core.publisher.Mono
+import reactor.core.scheduler.Schedulers
 import reactor.test.StepVerifier
 import spock.lang.Specification
 
@@ -50,7 +51,7 @@ class MultistreamSpec extends Specification {
         setup:
         def up1 = new EthereumPosRpcUpstreamMock("test1", Chain.ETHEREUM, TestingCommons.api(), new DirectCallMethods(["eth_test1", "eth_test2"]))
         def up2 = new EthereumPosRpcUpstreamMock("test1", Chain.ETHEREUM, TestingCommons.api(), new DirectCallMethods(["eth_test2", "eth_test3"]))
-        def aggr = new EthereumPosMultiStream(Chain.ETHEREUM, [up1, up2], Caches.default())
+        def aggr = new EthereumPosMultiStream(Chain.ETHEREUM, [up1, up2], Caches.default(), Schedulers.boundedElastic())
         when:
         aggr.onUpstreamsUpdated()
         def act = aggr.getMethods()
@@ -186,7 +187,7 @@ class MultistreamSpec extends Specification {
         def up1 = TestingCommons.upstream("test-1", "internal")
         def up2 = TestingCommons.upstream("test-2", "external")
         def up3 = TestingCommons.upstream("test-3", "external")
-        def multistream = new EthereumPosMultiStream(Chain.ETHEREUM, [up1, up2, up3], Caches.default())
+        def multistream = new EthereumPosMultiStream(Chain.ETHEREUM, [up1, up2, up3], Caches.default(), Schedulers.boundedElastic())
 
         expect:
         multistream.getHead(new Selector.LabelMatcher("provider", ["internal"])).is(up1.ethereumHeadMock)
@@ -254,7 +255,7 @@ class MultistreamSpec extends Specification {
     class TestEthereumPosMultistream extends EthereumPosMultiStream {
 
         TestEthereumPosMultistream(@NotNull Chain chain, @NotNull List<EthereumPosUpstream> upstreams, @NotNull Caches caches) {
-            super(chain, upstreams, caches)
+            super(chain, upstreams, caches, Schedulers.boundedElastic())
         }
 
         @NotNull