How to fetch logged in user from client using session token or api key

Technical Questions
1 
<service verb="get" noun="MyUserAccount" authenticate="anonymous-view">
        <out-parameters>
            <parameter name="loggedInUser"/>
        </out-parameters>
        <actions>
            <entity-find-one entity-name="moqui.security.UserAccount" value-field="loggedInUser">
                <field-map field-name="userId" from="ec.user.userId"/></entity-find-one>
        </actions>
    </service>

how fetch logged in user from client using session token or api key

2

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