Fix servlet exception accessing inputstream before the application

[pavolloffay]

This fixes accessing request inputstream/reader before the application for async requests. In other words the instrumentation could access input stream before the application - especially for async response.

This fixes the issue, however the instrumentation still tries to access the streams even though the application might not read the body at all. In the follow-up PR I will try to add a check to read the stream only if the app accessed it.

2021-01-25 05:35:34.391 [GraphQLServlet-4] INFO  g.k.s.HttpRequestHandlerImpl - Bad request: cannot create invocation input parser

java.lang.IllegalStateException: STREAMED

    at org.eclipse.jetty.server.Request.getReader(Request.java:1178) ~[jetty-server-9.4.30.v20200611.jar:9.4.30.v20200611]

    at graphql.kickstart.servlet.GraphQLPostInvocationInputParser.getGraphQLInvocationInput(GraphQLPostInvocationInputParser.java:33) ~[graphql-java-servlet-10.0.0.jar:?]

    at graphql.kickstart.servlet.HttpRequestHandlerImpl.handle(HttpRequestHandlerImpl.java:36) ~[graphql-java-servlet-10.0.0.jar:?]

    at graphql.kickstart.servlet.AbstractGraphQLHttpServlet.doRequest(AbstractGraphQLHttpServlet.java:148) ~[graphql-java-servlet-10.0.0.jar:?]

    at graphql.kickstart.servlet.AbstractGraphQLHttpServlet.lambda$doRequestAsync$2(AbstractGraphQLHttpServlet.java:136) ~[graphql-java-servlet-10.0.0.jar:?]

    at io.opentelemetry.javaagent.instrumentation.api.concurrent.RunnableWrapper.run(RunnableWrapper.java:28) [?:0.9.1]

    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [?:?]

    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [?:?]

    at java.lang.Thread.run(Unknown Source) [?:?]

Signed-off-by: Pavol Loffay p.loffay@gmail.com