Added Get Guild Member endpoint

javacord-api/src/main/java/org/javacord/api/entity/server/Server.java

@@ -1794,6 +1794,24 @@ default CompletableFuture<Void> deafenUser(User user, String reason) {
         return createUpdater().setDeafened(user, true).setAuditLogReason(reason).update();
     }
 
+    /**
+     * Requests a server member.
+     *
+     * @param user The user to request as a member.
+     * @return A future to get a server member if it exists in the server.
+     */
+    default CompletableFuture<User> requestMember(User user) {
+        return requestMember(user.getId());
+    }
+
+    /**
+     * Requests a server member.
+     *
+     * @param userId The user id of the member to request.
+     * @return A future to get a server member if it exists in the server.
+     */
+    CompletableFuture<User> requestMember(long userId);
+
     /**
      * Undeafens the given user on the server.
      *

javacord-core/src/main/java/org/javacord/core/entity/server/ServerImpl.java

@@ -1405,6 +1405,13 @@ public void selfUndeafen() {
                 this, getConnectedVoiceChannel(api.getYourself()).orElse(null), null, false);
     }
 
+    @Override
+    public CompletableFuture<User> requestMember(long userId) {
+        return new RestRequest<User>(getApi(), RestMethod.GET, RestEndpoint.SERVER_MEMBER)
+                .setUrlParameters(getIdAsString(), Long.toUnsignedString(userId))
+                .execute(result ->  new MemberImpl(api, this, result.getJsonBody(), null).getUser());
+    }
+
     @Override
     public CompletableFuture<Void> kickUser(User user, String reason) {
         return new RestRequest<Void>(getApi(), RestMethod.DELETE, RestEndpoint.SERVER_MEMBER)