feat: add simple HTTP post request example

Author: guidoschmidt

src/examples/networking/http-post.zig

@@ -0,0 +1,27 @@
+const std = @import("std");
+
+const Client = std.http.Client;
+
+pub fn main() !void {
+    const allocator = std.heap.page_allocator;
+
+    var response: std.Io.Writer.Allocating = .init(allocator);
+    defer response.deinit();
+
+    var client: Client = .{
+        .allocator = allocator,
+    };
+    defer client.deinit();
+
+    _ = try client.fetch(.{
+        .method = .POST,
+        .location = .{
+            .url = "https://echo.free.beeceptor.com",
+        },
+        .payload = "Hello World",
+        .response_writer = &response.writer,
+    });
+
+    const response_data = try response.toOwnedSlice();
+    std.debug.print("{s}\n", .{response_data});
+}