Add Marshalers for profiling signal type

Changes addressing review comments

Author: jhalliday

exporters/otlp/profiles/src/main/java/io/opentelemetry/exporter/otlp/profiles/InstrumentationScopeProfilesMarshaler.java

@@ -11,25 +11,26 @@
 import io.opentelemetry.exporter.internal.otlp.InstrumentationScopeMarshaler;
 import io.opentelemetry.proto.profiles.v1experimental.internal.ScopeProfiles;
 import java.io.IOException;
+import java.util.List;
 
 final class InstrumentationScopeProfilesMarshaler extends MarshalerWithSize {
 
   private final InstrumentationScopeMarshaler instrumentationScope;
-  private final ProfileContainerMarshaler[] profileContainerMarshalers;
+  private final List<ProfileContainerMarshaler> profileContainerMarshalers;
   private final byte[] schemaUrlUtf8;
 
   InstrumentationScopeProfilesMarshaler(
       InstrumentationScopeMarshaler instrumentationScope,
       byte[] schemaUrlUtf8,
-      ProfileContainerMarshaler[] profileContainerMarshalers) {
+      List<ProfileContainerMarshaler> profileContainerMarshalers) {
     super(calculateSize(instrumentationScope, schemaUrlUtf8, profileContainerMarshalers));
     this.instrumentationScope = instrumentationScope;
     this.schemaUrlUtf8 = schemaUrlUtf8;
     this.profileContainerMarshalers = profileContainerMarshalers;
   }
 
   @Override
-  protected void writeTo(Serializer output) throws IOException {
+  public void writeTo(Serializer output) throws IOException {
     output.serializeMessage(ScopeProfiles.SCOPE, instrumentationScope);
     output.serializeRepeatedMessage(ScopeProfiles.PROFILES, profileContainerMarshalers);
     output.serializeString(ScopeProfiles.SCHEMA_URL, schemaUrlUtf8);
@@ -38,7 +39,7 @@ protected void writeTo(Serializer output) throws IOException {
   private static int calculateSize(
       InstrumentationScopeMarshaler instrumentationScope,
       byte[] schemaUrlUtf8,
-      ProfileContainerMarshaler[] profileContainerMarshalers) {
+      List<ProfileContainerMarshaler> profileContainerMarshalers) {
     int size = 0;
     size += MarshalerUtil.sizeMessage(ScopeProfiles.SCOPE, instrumentationScope);
     size += MarshalerUtil.sizeRepeatedMessage(ScopeProfiles.PROFILES, profileContainerMarshalers);

exporters/otlp/profiles/src/main/java/io/opentelemetry/exporter/otlp/profiles/ProfilesRequestMarshaler.java

@@ -23,7 +23,7 @@
  */
 public final class ProfilesRequestMarshaler extends MarshalerWithSize {
 
-  public static final ProtoFieldInfo RESOURCE_PROFILES =
+  private static final ProtoFieldInfo RESOURCE_PROFILES =
       ExportProfilesServiceRequest.RESOURCE_PROFILES;
 
   private final ResourceProfilesMarshaler[] resourceProfilesMarshalers;

exporters/otlp/profiles/src/main/java/io/opentelemetry/exporter/otlp/profiles/ResourceProfilesMarshaler.java

@@ -45,7 +45,7 @@ static ResourceProfilesMarshaler[] create(Collection<ProfileContainerData> profi
             new InstrumentationScopeProfilesMarshaler(
                 InstrumentationScopeMarshaler.create(entryIs.getKey()),
                 MarshalerUtil.toBytes(entryIs.getKey().getSchemaUrl()),
-                entryIs.getValue().toArray(new ProfileContainerMarshaler[0]));
+                entryIs.getValue());
       }
 
       resourceProfilesMarshalers[posResource++] =