docs: Expand README with new API methods

Added detailed descriptions for several new API methods in the README. These include methods for reading and importing schemas, importing relationships, and checking multiple permissions in bulk. Each method's parameters and return values are clearly explained to provide a comprehensive understanding of their usage.

README.md

@@ -300,3 +300,97 @@ Retrieves the list of permissions for a specified resource, permission, and subj
 **Returns**
 
 - A task representing the asynchronous operation, with a list of string indicating the permissions for the specified resource.
+
+### ReadSchema
+
+Reads the current schema in use by the SpiceDB.
+
+**Returns**
+
+- A `string` representing the current schema as defined in the SpiceDB.
+
+### ImportSchemaFromFileAsync
+
+Imports a schema into SpiceDB from a specified file.
+
+**Parameters**
+
+- `filePath` - The path to the file containing the schema to import.
+
+**Returns**
+
+- A task representing the asynchronous operation of importing the schema.
+
+### ImportSchemaFromStringAsync
+
+Imports a schema into SpiceDB from a provided string.
+
+**Parameters**
+
+- `schema` - The schema to import, provided as a string.
+
+**Returns**
+
+- A task representing the asynchronous operation of importing the schema.
+
+### ImportRelationshipsFromFileAsync
+
+Imports relationships into SpiceDB from a specified file.
+
+**Parameters**
+
+- `filePath` - The path to the file containing the relationships to import.
+
+**Returns**
+
+- A task representing the asynchronous operation, with a `ZedToken?` indicating the version of the data after the import operation.
+
+### ImportRelationshipsAsync
+
+Imports relationships into SpiceDB from a provided string.
+
+**Parameters**
+
+- `content` - The relationships to import, provided as a string.
+
+**Returns**
+
+- A task representing the asynchronous operation, with a `ZedToken?` indicating the version of the data after the import operation.
+
+### CheckBulkPermissionAsync (IEnumerable<string> permissions)
+
+Checks multiple permissions in bulk for a specified list of permission identifiers.
+
+**Parameters**
+
+- `permissions` - An enumerable of permission identifiers to check.
+
+**Returns**
+
+- A task representing the asynchronous operation, with a `CheckBulkPermissionsResponse?` indicating the results of the bulk permission checks.
+
+### CheckBulkPermissionAsync (IEnumerable<Permission> permissions)
+
+Checks multiple permissions in bulk for a specified list of `Permission` objects.
+
+**Parameters**
+
+- `permissions` - An enumerable of `Permission` objects to check.
+
+**Returns**
+
+- A task representing the asynchronous operation, with a `CheckBulkPermissionsResponse?` indicating the results of the bulk permission checks.
+
+### CheckBulkPermissionAsync (IEnumerable<CheckBulkPermissionsRequestItem> items)
+
+Checks multiple permissions in bulk for a specified list of `CheckBulkPermissionsRequestItem` objects.
+
+**Parameters**
+
+- `items` - An enumerable of `CheckBulkPermissionsRequestItem` objects to check.
+
+**Returns**
+
+- A task representing the asynchronous operation, with a `CheckBulkPermissionsResponse?` indicating the results of the bulk permission checks.
+
+