You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: _efs_storage_configuration.rs
    path of file: ./repos/aws-sdk-rust/sdk/m2/src/types
    
    the code of the file until where you have to start completion: // Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.

/// <p>Defines the storage configuration for an Amazon EFS file system.</p>
#[non_exhaustive]
#[derive(::std::clone::Clone, ::std::cmp::PartialEq, ::std::fmt::Debug)]
pub struct EfsStorageConfiguration {
    /// <p>The file system identifier.</p>
    pub file_system_id: ::std::string::String,
    /// <p>The mount point for the file system.</p>
    pub mount_point: ::std::string::String,
}
impl EfsStorageConfiguration {
    /// <p>The file sy
    
    pub fn build(self) -> ::std::result::Result<crate::types::EfsStorageConfiguration, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::EfsStorageConfiguration {
            file_system_id: self.file_system_id.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "file_system_id",
                    "file_system_id was not specified but it is required when building EfsStorageConfiguration",
                )
            })?,
            mount_point: self.mount_point.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "mount_point",
                    "mount_point was not specified but it is required when building EfsStorageConfiguration",
                )
            })?,
        })
    }